WORM_CRIDEX.SADQ

This worm arrives as an attachment to email messages spammed by other malware/grayware or malicious users. 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 is injected into all running processes to remain memory resident.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself.

Arrival Details

This worm arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

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 component file(s):

• %User Temp%\{random name}.tmp.bat - deleted immediately

(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.)

It drops the following copies of itself into the affected system:

• %User Profile%\Application Data\KB{random number}.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It creates the following folders:

• %User Profile%\Application Data\{random folder}

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

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

It adds the following mutexes to ensure that only one of its copies runs at any one time:

• Local\XME{random}
• Local\XMM{random}
• Local\XMI{random}
• Local\XMS{random}
• Local\XMF{random}
• Local\XMR{random}
• Local\XMQ{random}
• Local\XMB{random}

It injects threads into the following normal process(es):

• explorer.exe

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
KB{random number}.exe = "%User Profile%\Application Data\KB{random number}.exe"

Other System Modifications

This worm adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\{random}

Propagation

This worm creates the following folders in all removable drives:

• {random folder}

It drops the following copy(ies) of itself in all removable drives:

• {random folder}\{random file name}.exe

Backdoor Routine

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

• Download and execute additional files
• Download other files
• Monitors cookies
• Steal login credentials
• Update itself
• Upload collected certificates and credentials

It connects to the following URL(s) to send and receive commands from a remote malicious user:

• http://{BLOCKED}y-up.ru/jsbqmCA/hCpyb/Cnw/ED/
• http://{BLOCKED}oktor.ru/jsbqmCA/hCpyb/Cnw/ED/
• http://{BLOCKED}am.ru/jsbqmCA/hCpyb/Cnw/ED/
• http://{BLOCKED}irect.ru/jsbqmCA/hCpyb/Cnw/ED/

However, as of this writing, the said sites are inaccessible.

Other Details

This worm deletes the initially executed copy of itself

NOTES:

This worm collects configuration data and stores the collected data in the following registry entry:

HKEY_CURRENT_USER\Software\Microsoft\Windows NT\{random}
{default} = "{config file}"

It monitors the following browsers:

• chrome.exe
• firefox.exe
• explorer.exe