Threat Descriptions

Trojan-Downloader:W32/Agent.FDA

Classification

Category :

Malware

Type :

Trojan-Downloader

Platform :

W32

Aliases :

Trojan-Downloader:W32/Agent.FDA

Summary

F-Secure has received multiple reports regarding a new trojan downloader that is being sent via email to a large number of recipients. The trojan downloader is attached to a message claiming to be a critical security update from Microsoft.

Removal

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

Trojan-Download:W32/Agent.FDA arrives via email messages claiming to be a critical security update from Microsoft.The messages have an attachment named update.zip and inside the attachment there is a trojan file named update.exe. The spammed messages contain the following text: 

Dear, customer
New bug in Windows Kernel was found. It makes your computer vulnerable. We strongly recommend you to install this Critical Update (in attacment).Best Regards, Microsoft Window Update.

At the bottom of spammed messages there usually is a piece of random text, an attempt to bypass spam filters. Here is a screenshot of one of the spammed messages:

When extracted and run by a user, the trojan-downloader connects to a website and downloads more malicious components.