Rule: -- Sid: 208 -- Summary: Phase0 is a Trojan Horse offering the attacker control of the victim host. This event is generated when the victim server replies to an attackers client connection request. -- Impact: Possible theft of data and control of the targeted machine leading to a compromise of all resources the machine is connected to. This Trojan also has the ability to delete data, steal passwords and disable the machine. -- Detailed Information: This Trojan affects the following operating systems: Windows 95 Windows 98 Windows ME Windows NT Windows 2000 The Trojan changes system registry settings to add the PhaseZero server to programs normally started on boot. Due to the nature of this Trojan it is unlikely that the attacker's client IP address has been spoofed. The default name of the server application is MsgServ. Server Port: 555 although this can be changed. -- Attack Scenarios: This Trojan may be delivered to the target in a number of ways. This event is indicative of an existing infection being activated. Initial compromise can be in the form of a Win32 installation program that may use the extension ".jpg" or ".bmp" when delivered via e-mail for example. -- Ease of Attack: This is Trojan activity, the target machine may already be compromised. Updated virus definition files are essential in detecting this Trojan. -- False Positives: None Known -- False Negatives: None Known -- Corrective Action: Edit the system registry to remove the extra keys or restore a previously known good copy of the registry. Affected registry keys are: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\ Registry keys added: MsgServ Delete the server program msgsvr32.exe and/or ServerS.exe. A reboot of the infected machine is recommended. -- Contributors: Original rule writer unknown Sourcefire Research Team Nigel Houghton <nigel.houghton@sourcefire.com> -- Additional References: Dark-e http://www.dark-e.com/archive/trojans/phase/ --