Threat Description

Trojan-Downloader: W32/Renos.Gen


Category: Malware
Type: Trojan-Downloader
Platform: W32
Aliases: Trojan-Downloader:W32/Renos.Gen


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


Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More scanning & removal options

More information on scanning or removal options is available in the documentation for your F-Secure security product on the Downloads section of our Home - Global site.

You may also refer to the Knowledge Base on the F-Secure Community site for more information.

Contact Support

For further assistance, F-Secure customers can request support online via the Request support or the Chat forms on our Home - Global site.

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.


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.


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.


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