TROJ_FAKEAV.CAY

This Trojan executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

Installation

This Trojan drops the following copies of itself into the affected system:

• %System%\wuaucldt.exe
• %User Profile%\wuaucldt.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
wuaucldt = %User Profile%\wuaucldt.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
wuaucldt = %System%\wuaucldt.exe

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

• http://{BLOCKED}.{BLOCKED}.151.194/jjnb.exe - detected as TSPY_SPYEYE.SMAE

It saves the files it downloads using the following names:

• %User Temp%\stfu.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.