WORM_SOHANAD.DU

This worm arrives by connecting affected removable drives to a system. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware. It is injected into all running processes to remain memory resident.

It drops copies of itself in all removable and physical drives found in the system. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It executes commands from a remote malicious user, effectively compromising the affected system.

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It 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 a copy of itself in the following folders using different file names:

• %System%\csrcs.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.)

It drops the following component file(s):

• %System%\autorun.inf - detected as Mal_Otorun1

(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.)

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

It is injected into all running processes to remain memory resident.

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

It modifies the following registry entry(ies) to enable its 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.)

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty

It modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0

(Note: The default value data of the said registry entry is 1.)

Propagation

This worm drops copies of itself in all removable and physical drives found in the system.

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=hmegtf.exe
;{garbage code}
shell\open\Command=hmegtf.exe
;{garbage code}
shell\open\Default=1
;{garbage code}
;{garbage code}
shell\explore\Command=hmegtf.exe
;{garbage code}

Backdoor Routine

This worm executes the following commands from a remote malicious user:

• Connect to a website
• Connect to an IRC channel to send receive commands
• Copy ,Download, Execute and Delete files
• Download malware plugins
• List Messenger Application contacts
• List active window titles
• List and terminate processes
• Query and manipulate registries
• Scan for IP addresses within the network
• Update itself

Download Routine

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

• http://ngs.{BLOCKED}m.cx/uhyvd.htm

Other Details

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

• www.whatismyip.com
• checkip.dyndns.org