JV/Exploit-Blacole.a

This page shows details and results of our analysis on the malware JV/Exploit-Blacole.a

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 email, malicious or hacked web pages, Internet Relay Chat (IRC), peer-to-peer networks, etc.

Aliases

    • F-Secure - Exploit.Java.CVE-2012-0507.N
    • Microsoft - Exploit:Java/CVE-2012-0507.D!ldr
    • NOD32 - Java/Exploit.CVE-2012-0507.D
    • Sophos - Exp/20120507-A


Minimum Engine

5600.1067

File Length

varies

Description Added

2012-04-05

Description Modified

2012-04-09

Malware Proliferation

Characteristics

"JV/Exploit-Blacole.a" is the detection for a malicious Java class files stored within a Java archive (.JAR) , which attempts to exploit a vulnerability in the Java Runtime Environment (JRE) up to and including versions 5 update 33,version 6 update 30 and version 7 update 2.

This exploit may be encountered when visiting a compromised webpage that contains the malicious code.

The code is created by an attacker using the "Blackhole" Exploit Kit and inserted into a compromised webpage.

When the page is visited by a user running vulnerable versions of Java, the malicious Java class runs and allows the execution of arbitrary code.

The vulnerability exploits a flaw in the deserialization of "AtomicReferenceArray" objects, which allows remote attackers to call system level Java functions via the ClassLoader of a constructor that is being deserialized without proper sandboxing.

The attacker may host a malicious script on a website. If a user visits the site, the script loads the Java applet.

The malicious Java package may contain the following malicious Java class files:

L.class [Detected as JV/Exploit-Blacole.a]

Ta.class [Detected as JV/Exploit-Blacole.a]

The file L.class triggers the vulnerability. The method init() builds the object AtomicReferenceArray for the execution of malicious Java code outside the sandbox.

And the other one (ta.class) is a loader class which creates another class (Eg: C.class) file at runtime and loads.

This class (C.class) downloads malware from a certain server and executes it.

Symptoms

Presence of above mentioned activities.

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