WORM_AUTORUN.CHO

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.

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:

• %Windows%\SYSTIM32.EXE
• %System%\SYSTIM32.EXE
• %Windows%\TEMP.000

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

It creates the following folders:

• {malware path}\SYSTIM32

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\Run
Expl0rer = "Systim32.exe"

Other System Modifications

This worm adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"

Dropping Routine

This worm drops the following files:

• %System Root%\regs.sys

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

NOTES:

It drops copies of itself in the malware path folder. These dropped copies use the names of the folders located on the said folder for their file names.