Trojan-Downloader:W32/Mebroot.gen!B

Classification

Malware

Trojan-Downloader

W32

Trojan-Downloader:W32/Mebroot.gen!B

Summary

Trojan-Downloader:W32/Mebroot.gen!B is a generic detection that identifies the downloader program responsible for fetching the installer for the Mebroot rootkit.

Security programs use generic detections that look for broad patterns of code or behavior to identify similar programs or files. If you suspect the file was incorrectly detected, go to: Removal: Resolving a False Positive.

Removal

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.

Resolving 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 to F-Secure Labs 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.

Find out more

Knowledge Base

Find the latest advice in our Community Knowledge Base.

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

This malware is discussed in further detail in the following Labs Weblog posts:

The downloader is known to be distributed to users via a malicious website (driveby download) or via an exploit.

Activity

When active, the downloader downloads an encrypted file on port 443 or 80 from:

  • http://bcoxgcgxes.com (encrypted file)

where (encrypted file) is a defined string. This string is unique in every sample.

Once downloaded, the encrypted file is first saved in an allocated memory where it will be decrypted, then saved to a file in a temporary folder. The file will then be executed.

The encrypted file is encrypted with an RC2 encryption algorithm. The Cipher Hash that is used in the decryption is based on a defined string that is also unique in every sample.

Date Created: -

Date Last Modified: -