WORM_UTOTI.SS

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

Arrival Details

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

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

• %System%\46781054.exe
• %System%\csrcs.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It drops the following files:

• %User Temp%\suicide.bat
• %System%\autorun.inf

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
csrcs = "%System%\csrcs.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
WMIX = "%System%\prexi.exe"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe csrcs.exe"

(Note: The default value data of the said registry entry is "Explorer.exe".)

Propagation

This worm drops the following copies of itself in all physical and removable drives:

• gqgdih.exe

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

;{garbage code}
[AuTOrUn
;{garbage code}
open=gqgdih.exe
;{garbage code}
shell\open\Command=gqgdih.exe
;{garbage code}
shell\open\Default=1
;{garbage code}

Dropping Routine

This worm drops the following files:

• %System%\prexi.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

This worm connects to the following URL(s) to get the affected system's IP address:

• http://www.whatismyip.com

It connects to the following possibly malicious URL:

• http://{BLOCKED}cluster.com:5300/po.php
• http://{BLOCKED}.19.236:4700/h.php