The Internet threat alert status is currently normal. At present, no major epidemics or other serious incidents have been recorded by Kaspersky Lab’s monitoring service. Internet threat level: 1


Detected Sep 28 2008 19:47 GMT
Released Sep 28 2008 23:47 GMT
Published Feb 20 2009 07:53 GMT

Technical Details
Removal instructions

Technical Details

This Trojan downloads other files via the Internet and launches them for execution on the victim machine. The program is an HTML page which contains Java Script scenarios. It is 1070 bytes in size.


If during launch, there is no “some=” cookie on the victim machine, the Trojan will create this cookie for 24 hours by using a vulnerability in Adobe Flash Player to connect to the following addresses:


At the time of writing, these links were not working.

The vulnerable ActiveX element has the following unique identifier in the system registry:


Removal instructions

If your computer does not have an up-to-date antivirus, or does not have an antivirus solution at all, follow the instructions below to delete the malicious program:

  1. Delete the original Trojan file (the location will depend on how the program originally penetrated the victim machine).
  2. Delete all files from %Temporary Internet Files%.
  3. Disable the vulnerable ActiveX object (see How to stop an ActiveX control from running in Internet Explorer)
  4. Update your antivirus databases and perform a full scan of the computer (download a trial version of Kaspersky Anti-Virus).

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Programs classified as Trojan-Downloader download and install new versions of malicious programs, including Trojans and AdWare, on victim computers. Once downloaded from the Internet, the programs are launched or included on a list of programs which will run automatically when the operating system boots up.

Information about the names and locations of the programs which are downloaded are in the Trojan code, or are downloaded by the Trojan from an Internet resource (usually a web page).

This type of malicious program is frequently used in the initial infection of visitors to websites which contain exploits.

Other versions


Trojan-Downloader.JS.Agent.crh (Kaspersky Lab) is also known as:

  • Troj/PHPSmall-A (Sophos)
  • PHP/Small.B (FPROT)
  • Backdoor.PHP.ALI (BitDef7)
  • PHP.ShellBot.M (VirusBuster)
  • Backdoor.PHP.Small.o (Ikarus)
  • JS/Downloader.Agent (AVG)
  • Trojan.DL.Script.JS.MS06014.b (Rising)