WORM_ROMBRAST.AD

This worm is an emerging toolkit seen in the black market. It has the potential to be the next hot botnet malware, similar to DORKBOT.

To get a one-glance comprehensive view of the behavior of this Worm, refer to the Threat Diagram shown below.

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 is injected into all running processes to remain memory resident.

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. It connects to a website to send and receive information.

It also has rootkit capabilities, which enables it to hide its processes and files from the user.

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 and executes them:

• %Application Data%\{random}\{random}.exe

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

It drops the following files:

• %Application Data%\{random}\{random}.log
• %Application Data%\{random}\{random}.cfg

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

It creates the following folders:

• %Application Data%\{random}

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

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\Run
{random} = "%Application Data%\{random}\{random},exe"

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random} = "%Application Data%\{random}\{random},exe"

Propagation

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

• {random}_l.exe
• {random}_a.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:

[autorun]
open={random}_a.exe

Backdoor Routine

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

• Visit URL
• Form Grabber (Chrome, IExplore, Firefox)
• UDP / SYN / Slowloris Flooding
• Download and execute arbitrary files
• Update / Uninstall itself
• DNS Hook
• FTP Grabber

It connects to the following websites to send and receive information:

• {pseudorandom}.{BLOCKED}chsecurity.biz
• {pseudorandom}.{BLOCKED}tversion1.biz
• {pseudorandom}.{BLOCKED}x.biz

Rootkit Capabilities

This worm also has rootkit capabilities, which enables it to hide its processes and files from the user.

NOTES:

This worm drops the following shortcut link in removable drives to load the malware using folder names found on the device:

• {drive letter}:\{folder name}.lnk - detected as LNK_JORIK.SMC