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Downloader-ASH.gen.b!​1D22B10B

This page shows details and results of our analysis on the malware Downloader-ASH.gen.b!1D22B10B

Threat Detail

Malware Type: Trojan

Malware Sub-type: Downloader

Discovery Date: 2008-09-15

Next Steps:

Overview

This is a Trojan detection. Unlike viruses, Trojans do not self-replicate. They are spread manually, often under the premise that they are beneficial or wanted. The most common installation methods involve system or security exploitation, and unsuspecting users manually executing unknown programs. Distribution channels include e-mail, malicious or hacked Web pages, Internet Relay Chat (IRC), peer-to-peer networks, etc.


Minimum DAT

5384 (2008-09-15)

Updated DAT

5384 (2008-09-15)

 Minimum Engine

5.3.00

File Length

199168

 Description Added

2008-09-15

Description Modified

2008-09-15

Malware Proliferation

Characteristics

File PropertyProperty Value
FileNamescan~1.exe
McAfee DetectionDownloader-ASH.gen.b
Length199,168 bytes
CRC1D22B10B
MD5EB51B5A672A4DDC2E50C7FAAF3EC1E06
SHA11B7B1048BA4E8CB79BB379E858A48780A87DE77E

Other Common Detection Aliases

Company NameDetection Name
AVG (GriSoft)downloader.generic7.aowl
KasperskyBackdoor.Win32.Frauder.fk
microsofttrojandownloader:win32/renos.as

Avert® Labs has observed the following system activities:

ActivityRisk Level
Modifies the operating system security policy
Critical
Enumerates running processes
Medium
Uses shared memory of other processes
Low
Writes executable in the windows folder
Low
Creates registry keys and data values to persist on OS reboot
Informational

Other detections that have been observed.

FileNameMcAfee Supported
%USERPROFILE%\local settings\temp\.tt2.tmp.vbs
VBS/FakeAlert-AB

System Changes

These are general defaults for typical path variables. (Although they may differ, these examples are common.):
%WinDir% = \WINDOWS (Windows 9x/ME/XP/Vista), \WINNT (Windows NT/2000)
%SystemDir% = \WINDOWS\SYSTEM (Windows 98/ME), \WINDOWS\SYSTEM32 (Windows XP/Vista), \WINNT\SYSTEM32 (Windows NT/2000)
%ProgramFiles% = \Program Files

The following files have been added to the system:

  • %WINDIR%\system32\blphcco1j0e77r.scr
  • %WINDIR%\system32\phcco1j0e77r.bmp

    • The following registry elements have been created:

  • hkey_local_machine\software\microsoft\software notifier\
    • installid = e854247f-7180-445e-8127-6c20adf48fc1
  • hkey_users\s-1-5-21-1202660629-602609370-839522115-500\software\microsoft\windows\currentversion\policies\system\
    • nodispbackgroundpage = 1
    • nodispscrsavpage = 1
  • hkey_users\s-1-5-21-1202660629-602609370-839522115-500\software\sysinternals\bluescreen screen saver\
    • eulaaccepted = 1

    • The following registry elements have been changed:

  • hkey_local_machine\software\microsoft\windows\currentversion\run\
    • lphcco1j0e77r = c:\windows\system32\lphcco1j0e77r.exe
  • hkey_users\s-1-5-21-1202660629-602609370-839522115-500\control panel\colors\
    • background = 0 0 255
  • hkey_users\s-1-5-21-1202660629-602609370-839522115-500\control panel\desktop\
    • convertedwallpaper = c:\windows\system32\phcco1j0e77r.bmp
    • originalwallpaper = c:\windows\system32\phcco1j0e77r.bmp
    • screensaveactive = 49
    • screensavetimeout = 3158070
    • scrnsave.exe = c:\windows\system32\blphcco1j0e77r.scr
    • tilewallpaper = 48
    • wallpaper = c:\windows\system32\phcco1j0e77r.bmp
    • wallpaperstyle = 48

    • The applications created the following network connection(s):

  • http
    • hxxp://windowsupdate.microsoft.com/
    • hxxp://windowsupdate.microsoft.com/images/1186435832
      /30a05452d5cfc2a7c8bf694c8198b5e7
      /*****************************************

    • Symptoms

    This symptoms of this detection are the files, registry, and network communication referenced in the characteristics section.

    Method of Infection

    Trojans do not self-replicate. They are spread manually, often under the premise that the executable is something beneficial. Distribution channels include IRC, peer-to-peer networks, newsgroup postings, e-mail, etc.

    Removal

    All Users:

    Please use the following instructions for all supported versions of Windows to remove threats and other potential risks:

    1.Disable System Restore .

    2.Update to current engine and DAT files for detection and removal.

    3.Run a complete system scan.

    Modifications made to the system Registry and/or INI files for the purposes of hooking system startup, will be successfully removed if cleaning with the recommended engine and DAT combination (or higher).

    1. Please go to the Microsoft Recovery Console and restore a clean MBR.

    On windows XP:

    Insert the Windows XP CD into the CD-ROM drive and restart the computer.
    When the "Welcome to Setup" screen appears, press R to start the Recovery Console.
    Select the Windows installation that is compromised and provide the administrator password
    Issue 'fixmbr' command to restore the Master Boot Record
    Follow onscreen instructions
    Reset and remove the CD from CD-ROM drive.


    On Windows Vista and 7:

    Insert the Windows CD into the CD-ROM drive and restart the computer.
    Click on "Repair Your Computer"
    When the System Recovery Options dialog comes up, choose the Command Prompt.
    Issue 'bootrec /fixmbr' command to restore the Master Boot Record
    Follow onscreen instructions
    Reset and remove the CD from CD-ROM drive.

    Variants

    United States - English