Trojan-Downloader:W32/Renos.Gen

Classification

Malware

Trojan-Downloader

W32

Trojan-Downloader:W32/Renos.Gen

Summary

Trojan-Downloader:W32/Renos.GEN is a generic detection for variants in the Trojan-Downloader:W32/Renos family.

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: Suspect a file is incorrectly detected (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.

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.

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

Renos variants are trojan-downloaders that download rogueware onto the system. The trojan may arrive on the system as part of another malware's payload, from a user-initiated download, or through other means. The downloaded programs attempt to persuade the user to buy a particular rogue antispyware application by pretending that the system is infected with spyware.

Installation

On installation, the trojan drops the file

  • %WINDOWS%/system32/brastk.exe

and then creates a launchpoint for it. The brastk.exe file then attempts to download another file from a remote server.

Execution

On execution, this trojan will modify registry keys in order to bypass the Windows firewall, then download a rogue antispyware application from a remote server and save it onto the system, most commonly at:

  • %windir%\system32\winil104552502.exe

The actual save location may vary depending on the variant.

The malware subsequently creates a system tray icon that periodically displays the following message:

"Your computer is infected!

Windows has detected spyware infection!
 It is recommended to use special antispyware tools to prevent data loss.

Windows will now download and install the most up-to-date antispyware for you.
 Click here to protect your computer from spyware!"

Clicking on the message will launch the downloaded rogue antispyware application.