Threat Descriptons



Category :


Type :


Aliases :

Trojan-Downloader:JS/Agent.CKL, Trojan-Downloader.JS.Agent.ckl


This type of trojan secretly downloads malicious files from a remote server, then installs and executes the files.


Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Upon execution, this trojan will try to take advantage of the following vulnerabilities:

  • Microsoft Office Snapshot Viewer ActiveX vulnerability
  • Sina DLoader Class ActiveX Control 'DonwloadAndInstall' Method Arbitrary File Download Vulnerability
  • Internet Explorer (MDAC) Remote Code Execution Exploit (MS06-014)
  • UUSee UUUpgrade ActiveX Control 'Update' Method Arbitrary File Download Vulnerability
  • Ourgame 'GLIEDown2.dll' ServerList Method ActiveX Control Remote Code Execution Vulnerability
  • RealPlayer IERPCtl.IERPCtl.1 (CVE-2007-5601)
  • Baidu Soba Remote Code Execute Vulnerability
  • DPClient.Vod (CVE-2007-6144)

If any of these vulnerabilities are present on the user's system, the malware will exploit it in order to download and execute files from the following sites:

  •[...]/a2.css - Trojan.Win32.Agent.wnu
  •[...]/sina.exe - Trojan.Win32.Agent.wnu
  •[...]/ - Trojan-Downloader.Win32.Agent.wps
  •[...]115.swf -
  •[...]115.swf -
  •[...]/UU.ini - unavailable

The online F-Secure Health Check can help determine whether a user's system has vulnerabilities which can be exploited, and assist in finding fixes for any vulnerabilities discovered.

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