Backdoor:W32/IRCBot.AAS

Classification

Type:Backdoor

Backdoor.Win32.IRCBot.AAS

Summary

A remote administration tool (RAT) that bypasses the security features of a program, computer or network to give unauthorized access or control to its user.

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

Check for the latest database updates
First check if your F-Secure security program is using the latest updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.

Technical Details

This IRCBot connects to an IRC server at dark.bestunix.org, where it waits for commands from a remote user. The bot is controlled via messages sent to it.

Installation

Upon execution, Backdoor.Win32.IRCBot.AAS drops a copy of itself in the Windows System directory as:

algose32.exe

This program takes advantage of the MS06-040 vulnerability. A specially crafted packet is embedded in the body of the program and is XOR'ed by 99h. The program will then wait for a "Scan" command from a remote user.

On receiving the command, the program sends the packet to all IP addresses that the remote user specifies. The payload of the packet is that it downloads a file from a URL and executes it. The URL the file is downloaded from is:

http://www.emr3.net/p[...].exe.

The file downloaded is detected as Backdoor.Win32.IRCBot.WT.

Activity

This malware connects to an IRC server and joins the password-protected channel #!e!, using a random nickname. It then waits for commands from a remote user.

To be able to gain access to the backdoor, the remote user must login to the channel and type the password:

When successfully logged in to the BOT, the remote user can do the following IRC commands:

Joins/Part an IRC channel
Send private/channel messages
Change the BOT's nick
Quits the IRC server.
Checks the BOT's ID and version.
Check the up-time of the BOT
Logout from the BOT.
Update the BOT.

The remote user can also perform the following system commands:

Opens/Executes/Downloads files.
Port scanning.
Access files through a Shell.
List/Terminate processes.

Registry

This program creates the following registry key as its auto-start technique:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run Offices Monitorse = "%systemdir%\algose32.exe"
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run Offices Monitorse = "%systemdir%\algose32.exe"

Note: %systemdir% is typically "C:\Windows\system32".