Trojan-Downloader.JS.Agent.gcv

Technical Details
Payload
Removal instructions

Technical Details

A trojan program that uses the vulnerabilities in Oracle Java and Adobe Reader/Acrobat products to download and launch other malware. It is a HTML document containing Java Script. 45082 bytes.

Payload

After opening the malicious HTML page in the browser, it displays the following message:

404 Not Found

Then, using Java Script, the trojan collects system information, in particular:

• The type of OS:

  Win
  Mac
  Linux
  FreeBSD
  iPhone
  iPod
  iPad
  Win.*CE
  Win.*Mobile
  Pocket PC
  

• The installed browser:

  MS Internet Explorer
  Mozilla Firefox
  Safari
  Chrome
  Opera
  

• Plugins installed on the browser and ActiveX objects.
• MIME types supported by the browser.
• Versions of Java and AdobeReader installed.

The trojan then tries to launch the Java-applet located at the following link in the user's browser:

http://<domain_name_of the infected_server>/games/getJavaInfo.jar

If the system has Java version 5, update 23 or below or version 6, update 18 or below installed, the trojan tries to launch the applet located at the following link in the user's browser:

http://<domain_name_of the infected_server>/games/worms.jar

starting it with the following parameters:

name=' prm'
value='<encrypted_link>'

The following class name is issued for the applet, as the main class:

xmlTools.XMLMaker.class

To implement additional malicious scripts, the trojan activates the following ActiveX objects:

Msxml2.XMLHTTP
Msxml2.DOMDocument
Microsoft.XMLDOM
ShockwaveFlash.ShockwaveFlash
TDCCtl.TDCCtl
Shell.UIHelper
Scripting.Dictionary
wmplayer.ocx

To implement Java applications in the browser, the trojan determines the following MIME types:

application/x-java-applet
application/x-java-vm
application/x-java-bean
application/x-java-applet
application/npruntime-scriptable-plugin;deploymenttoolkit
application/java-deployment-toolkit

Using the vulnerability in the Java Deployment Toolkit (JDT) on account of the incorrect URL processing which allows the attacker to transfer arbitrary parameters in Java Web Start (JWS) (CVE-2010-0886), the attacker forms a special link and transfers this as a parameter of the vulnerable "launch()" function. This means that the trojan, disguised as a media file, then launches the malicious Java-applet:

\\193.**.**.86\pub\new.avi

which downloads and launches the malicious file located at the following link:

http://ktr***.cc/d.php?f=360&e=2

To implement the malicious script in MS Internet Explorer, the trojan uses ActiveX objects with the following unique identifiers:

{CAFEEFAC-DEC7-0000-0000-ABCDEFFEDCBA}
{8AD9C840-044E-11D1-B3E9-00805F499D93}

If you have installed Java version 6, update 23, the trojan tries to open the following web resource in the hidden frame:

http://<domain_name_of the infected_server>/games/java_trust.php?f=360

It also searches for the plugin installed in the "Windows Media Player" browser and, if it finds it, tries to download the exploit located at the following link in the hidden frame:

http://<domain_name_of the infected_server>/games/pch.php?f=360

The trojan then determines the plugins and ActiveX objects Adobe Reader and Adobe Acrobat installed in the browser. To run the malicious scripts in MS Internet Explorer, the trojan uses an ActiveX object with the following unique identifier:

{CA8A9780-280D-11CF-A24D-444553540000}

For implementation in Mozilla and in other NPAPI browsers, the trojan determines the following MIME types:

application/vnd.adobe.pdfxml
application/vnd.adobe.x-mars

Vulnerable versions of Adobe Reader include version 8.0.0 and earlier and all versions of Adobe Reader up to 9.3.1. Depending on the version of "PDF Reader" installed, it opens the malicious PDF document from one of the following links:

http://<domain_name_of the infected_server>/games/1fdp.php?f=360
http://<domain_name_of the infected_server>/games/1fdp.php?f=360

These links did not work when creating the description.

Removal instructions

If your computer has not been protected with anti-virus software and has been infected with malware, you will need to take the following actions to delete this:

1. Delete the original trojan file (its location on the infected computer will depend on how the program got onto the computer).
2. Clear the Temporary Internet Files directory containing the infected files (How to delete infected files in the Temporary Internet Files folder?):

   %Temporary Internet Files%

3. Update JRE and JDK to the latest versions.
4. Install the following updates:
   http://www.microsoft.com/technet/security/Bulletin/MS10-042.mspx
5. Install the latest version of Adobe Reader and Adobe Acrobat.
6. Disable the vulnerable ActiveX objects (How to stop launching the ActiveX control element in the Internet Explorer browser).
7. Run a full Kaspersky Antivirus scan of the computer with updated antivirus databases (download trial version).

[MD5: 268c0fde6d0559931657330fe803f44b]
[SHA1: 69b665549871da20343e857808efe08248e4dfc3]