Sophos

W32/Rbot-RI

Aliases
  • Backdoor.Win32.Rbot.gen
Category
Type
What to do
Prevalence low high

Summary

 
How it spreads
  • Network shares
Affected operating systems Windows
Characteristics
  • Installs itself in the registry
Included in our products from July 2005 (3.95)
Protection available since 7 December 2004 09:10:06 (GMT)
Last updated 19 May 2005 12:25:58 (GMT)
Detected by All Sophos products

Action

Please follow the instructions for removing worms.

You will also need to edit the following registry entries, if they are present. Please read the warning about editing the registry.

At the taskbar, click Start|Run. Type 'Regedit' and press Return. The registry editor opens.

Before you edit the registry, you should make a backup. On the 'Registry' menu, click 'Export Registry File'. In the 'Export range' panel, click 'All', then save your registry as Backup.

Locate the HKEY_LOCAL_MACHINE entries:

HKLM\Software\Microsoft\Windows\CurrentVersion\Run

HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices

and remove any reference to any file you deleted.

Each user has a registry area named HKEY_USERS\[code number indicating user]\. For each user locate the entry:

HKU\[code number]\Software\Microsoft\Windows\
CurrentVersion\Run\

and remove any reference to any file you deleted.

Close the registry editor.

More Information

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.

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