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
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:
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.