JS:Trojan.JS.Agent.[variant], Trojan-Downloader.JS.Agent.[variant]


Trojan-Downloader:JS/Agent is a large family of programs that secretly download, install and execute harmful files.

Automatic action

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.

Suspect a file is incorrectly detected (a False Positive)?

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 detection database 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.

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User Guide

See the user guide for your product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

Technical Details

Variants in the Trojan-Downloader:JS/Agent family are usually distributed as JavaScript (JS) files. The file may also be obfuscated to make them harder to analyze.

Users typically encounter these files in one of the following scenarios:

  • When browsing a legitimate website that has been compromised to host harmful files
  • When redirected by another threat to a malicious or fake website that hosts the harmful files
  • As a file attached to a spam or targeted email

Trojan-Downloader:JS/Agent variants often use social engineering. This usually involves making the file, spam email or fake website look legitimate or desirable enough to lure the user into voluntarily running the JS file.

When the file is launched, it will silently contact a remote server, then download and save additional harmful files onto the device. It can then run the downloaded files.

Some Trojan-Downloader:JS/Agent variants will also exploit vulnerabilities in the device to perform the file downloads.

Notable Trojan-Downloader:JS/Agent variants include: