WORM_WERGIMOG.TH

This worm arrives via removable drives. 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 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 via removable drives.

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 the following copies of itself into the affected system:

• %Application Data%\Microsoft\service{random numbers}.exe
  or
  
• %System%\service{random numbers}.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Adobe Reader Speed Launcher = "%System%\service{random numbers}.exe" or "%Application Data%\Microsoft\service{random numbers}.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Adobe Reader Speed Launcher = "%System%\service{random numbers}.exe" or "%Application Data%\Microsoft\service{random numbers}.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Adobe Reader Speed Launcher = "%System%\service{random numbers}.exe" or "%Application Data%\Microsoft\service{random numbers}.exe"

Other System Modifications

This worm adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\pPkzmsiesk
ISkxnksnam = "{random values}"

Propagation

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

• {Drive Letter}:\RECYCLER\autorun.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}
[autorun]
;{garbage}
action=Open folder to view files
;{garbage}
icon=shell32.dll,4
;{garbage}
open=RECYCLER\autorun.exe
;{garbage}
shell\Explore=Explore
;{garbage}
shell\Explore\command=RECYCLER\autorun.exe
;{garbage}
shell=Explore
;{garbage}
UseAutoPlay=1
;{garbage}

Other Details

This worm connects to the following possibly malicious URL:

• v2z.{BLOCKED}hak.biz:2040

NOTES:

This worm creates shortcut files (.LNK) that use the names of the folders located on the root directory of the drives for their file names. It then sets the attributes of the original folders/files to Hidden and System to trick users into clicking the .LNK files.