W32.Gaobot.ZX

W32.Gaobot.ZX is a minor variant of W32.Gaobot.SY. This worm attempts to spread through network shares with weak passwords, and it also allows attackers to access an infected computer using a predetermined IRC channel.

The worm uses multiple vulnerabilities to spread, including:

• The DCOM RPC vulnerability (described in Microsoft Security Bulletin MS03-026) using TCP port 135.
• The WebDav vulnerability (described in Microsoft Security Bulletin MS03-007) using TCP port 80.
• The Workstation service buffer overrun vulnerability (described in Microsoft Security Bulletin MS03-049) using TCP port 445. Windows XP users are protected against this vulnerability if Microsoft Security Bulletin MS03-043 has been applied. Windows 2000 users must apply MS03-049.
• The Microsoft Messenger Service Buffer Overrun Vulnerability (described in Microsoft Security Bulletin MS03-043).
• The Locator service vulnerability (described in Microsoft Security Bulletin MS03-001) using TCP port 445. The worm specifically targets Windows 2000 machines using this exploit.
• The UPnP vulnerability (described in Microsoft Security Bulletin MS01-059).
• The vulnerabilities in the Microsoft SQL Server 2000 or MSDE 2000 audit (described in Microsoft Security Bulletin MS02-061), using UDP port 1434.
• Sending itself to the backdoor ports that the Beagle and Mydoom families of worms open.

This variant is often compressed with Yoda's Cryptor, PE_Patch, and UPX.

Note: Virus definitions released April 16, 2004 contained a modification to this detection to account for the discovery of a minor variant.

Protection

• Initial Rapid Release version April 13, 2004
• Latest Rapid Release version July 19, 2008 revision 019
• Initial Daily Certified version April 13, 2004
• Latest Daily Certified version July 19, 2008 revision 018
• Initial Weekly Certified release date April 14, 2004

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Threat Assessment

Wild

• Wild Level: Medium
• Number of Infections: 50 - 999
• Number of Sites: More than 10
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Moderate

Damage

• Damage Level: Medium

Distribution

• Distribution Level: Medium