W32/Rbot-RI is a network worm which attempts to spread via network shares. The worm contains backdoor functions that allow unauthorised remote access to the infected computer via IRC channels while running in the background.
The worm spreads to network shares with weak passwords and also by using the LSASS security exploit (MS04-011) and the RPC-DCOM security exploit (MS03-039).
When run W32/Rbot-RI moves itself to the Windows System folder as a hidden, read-only, system file named wserb32.exe.
The worm then creates the following registry entries so as to run itself on computer logon:
HKCU\Software\Microsoft\Windows\CurrentVersion\Run
Microsoft ErgoPack
wserb32.exe
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
Microsoft ErgoPack
wserb32.exe
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Microsoft ErgoPack
wserb32.exe
W32/Rbot-RI then creates and logs messages to the file C:\.wser32.1.exe.
Once installed, W32/Rbot-RI will attempt to partake in distributed denial of service (DDoS) attacks, download and run files from the internet, steal CD keys and create a SOCKS4 server when instructed to do so by a remote attacker.
The worm will also attempt to log keystrokes and store the information in %SYSTEM%\keys.txt.
Sophos's anti-virus products include proactive protection technology, which can defend against new threats without requiring an update. Sophos customers have been protected against W32/Rbot-RI (detected as W32/Rbot-Fam) since version 3.88.