05/04/04 - W32/Sasser.worm.d
This variant of W32/Sasser.worm functions in a similar fashion as the original variant, with the following exceptions.
This variant spreads with the filename SKYNETAVE.EXE (16,384 bytes)
It sends ICMP echo packets to discover potential victims
It creates a remote shell on TCP Port 9995 rather than 9996
This self-executing worm spread by exploiting a Microsoft Windows vulnerability [MS04-011 vulnerability (CAN-2003-0533)]
Unlike many recent worms, this virus does not spread via email. No user intervention is required to become infected or propagate the virus further. The worm works by instructing vulnerable systems to download and execute the viral code.
Note: Infected systems should install the Microsoft update to be protected from the exploit used by this worm. See:
http://www.microsoft.com/technet/security/bulletin/MS04-011.mspx
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Symptoms
The virus copies itself to the Windows directory as SKYNETAVE.EXE and creates a registry run key to load itself at startup
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\Run "skynetave.exe" = %WinDir%\skynetave.exe
As the worm scans random IP addresses it listens on successive TCP ports starting at 1068. It also acts as an FTP server on TCP port 5554, and creates a remote shell on TCP port 9995.
A file named win2.log is created on the root of the C: drive. This file contains an IP address together with the number of machines infected.
Copies of the worm are created in the Windows System directory as #_up.exe. (Where '#' represents a string 4 or 5 digits.)
Examples
c:\WINDOWS\system32\26347_up.exe
c:\WINDOWS\system32\5157_up.exe
A side-effect of the worm is for LSASS.EXE to crash, by default such a system will reboot after the crash occurs. The following Window may be displayed:
More info on this worm:
http://vil.nai.com/vil/content/v_125012.htm Removal Instructions
Go to the following website for removal instructions:
http://vil.nai.com/vil/content/v_125012.htm Download Stinger to Scan for infection:
http://vil.nai.com/vil/stinger |
