W32/Rbot-FZB is a worm with IRC backdoor functionality for the Windows platform.
W32/Rbot-FZB spreads to other network computers by:
- exploiting common buffer overflow vulnerabilities, including: LSASS (MS04-011), SRVSVC (MS06-040), RPC-DCOM (MS04-012) and ASN.1 (MS04-007)
- networks protected by weak passwords
- AOL Instant Messenger
W32/Rbot-FZB is registered as a new system driver service named "icrss manager 32bit" with a display name of "icrss manager 32bit" and a startup type of automatic, so that it is started automatically during system startup. Registry entries are created under:
HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_ICRSS\
HKLM\SYSTEM\CurrentControlSet\Services\icrss
W32/Rbot-FZB runs continuously in the background, providing a backdoor server which allows a remote intruder to gain access and control over the computer via IRC channels.
W32/Rbot-FZB includes functionality to access the internet and communicate with a remote server via HTTP.
When first run W32/Rbot-FZB copies itself to <System>\icrss.exe.