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 Jun 25 2011 16:17 GMT
Released Jun 25 2011 18:53 GMT
Published Oct 10 2011 07:06 GMT

Technical Details
Removal instructions

Technical Details

A trojan program that downloads other software to the computer without the user's knowledge and launches this software for execution. It is Java Script (JS). The malicious script is 402 bytes.


After opening the infected page in the browser, the trojan will try to open the resource located at the following link in the hidden frame:
The link 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. Run a full Kaspersky Antivirus scan of the computer with updated antivirus databases (download trial version).

    [MD5: 15bbc1a99f7e13375021f803fc2eef17] [SHA1: 1ee7bb5cb7620aab5ae4ffeddbac603ea472a986]

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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.Iframe.chf (Kaspersky Lab) is also known as:

  • Mal/ObfJS-AB (Sophos)
  • JS.Iframe-6 (ClamAV)
  • Exploit:HTML/IframeRef.V (MS(OneCare))
  • JS.IFrame.143 (DrWeb)
  • JS/Kryptik.BM trojan (Nod32)
  • JS.Iframe.Gen.29 (VirusBuster)
  • JS:ScriptSH-inf [Trj] (AVAST)
  • Exploit.JS (Ikarus)
  • HTML/Framer (AVG)
  • JS/Agent.zbh (AVIRA)
  • JS/IFrame.FU (Norman)
  • Trojan.Script.JS.Iframe.j (Rising)
  • Trojan.Exploit.ANSN [Aquarius] (FSecure)
  • JS.Iframe.Gen.29 (VirusBusterBeta)
  • JS/Iframe.CHF!tr (Fortinet)