Backdoor:Win32/IRCbot.BH is a generic detection for a backdoor trojan that connects to an IRC server to receive commands from an attacker. This trojan contains code that exploits vulnerable Windows computers that have not applied
Security Bulletin MS08-067.
System Changes
The following system changes may indicate the presence of this malware:
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The presence of one of the following files:
%ProgramFiles%\mediaavi.exe
%ProgramFiles%\msgaurd.exe
%ProgramFiles%\soundmax.exe
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The presence of one of the following registry values and data:
Value: "MS Gaurd Driver"
With data: "%ProgramFiles%\msgaurd.exe"
Value: "SoundMAX Driver"
With data: "%ProgramFiles%\soundmax.exe"
Value: "MediaAVI Driver"
With data: "%ProgramFiles%\mediaavi.exe"
To subkeys:
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Backdoor:Win32/IRCbot.BH is a generic detection for a backdoor trojan that connects to an IRC server to receive commands from an attacker. This trojan contains code that exploits vulnerable Windows computers that have not applied
Security Bulletin MS08-067.
Installation
When executed, Win32/IRCbot.BH copies itself to the "Program Files" folder as an executable. In the wild, this trojan has used the following file names:
mediaavi.exe
msgaurd.exe
soundmax.exe
The registry is then modified to run the dropped copy at each Windows start, however, the key values and data may differ among variants of this trojan, as shown in the examples below:
Adds value: "MS Gaurd Driver"
With data: "%ProgramFiles%\msgaurd.exe"
Adds value: "SoundMAX Driver"
With data: "%ProgramFiles%\soundmax.exe"
Adds value: "MediaAVI Driver"
With data: "%ProgramFiles%\mediaavi.exe"
To subkeys:
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
While executing, the trojan remains resident in memory and connects to a predefined remote IRC server and awaits commands from an attacker. Commands could include sending the trojan to other computers in a worm-like manner using hard-coded exploits.
Payload
Bypasses Windows Firewall
Win32/IRCbot.BH modifies the registry to add the trojan to the Windows Firewall authorized applications list:
Adds value: "<Win32/IRCbot.BH path and filename>"
With data: "enabled:soundmax driver:*:<Win32/IRCbot.BH path and filename>"
To subkey: HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\List
Backdoor Functionality: Port 6556/ Spreads Via Explot
This trojan attempts to connect to a predefined remote IRC server named '0x90.devtech.us'. The connection is made using TCP port 6556 where upon connection, the trojan joins a preselected channel and awaits commands from an attacker. Using this backdoor, the attacker can order IRCbot.BH to attempt to spread.
If the vulnerability is successfully exploited, Win32/IRCbot.BH instructs the target computer to download and execute a copy of itself from the attacking computer.
Retrieves Potentially Sensitive Data
Win32/IRCbot.BH could be instructed to retrieve data from the clipboard and save it allowing an attacker to obtain potentially sensitive data.
Additional Information
This trojan contains the following strings which may vary among variants:
Purple 0.1c
#Purple-Exploit#
Analysis by Chris Jones & Patrick Nolan
Take the following steps to help prevent infection on your system:
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Enable a firewall on your computer.
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Use up-to-date antivirus software.
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Use caution when opening attachments and accepting file transfers.
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Use caution when clicking on links to web pages.
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Protect yourself against social engineering attacks.
Enable a firewall on your computer
Use a third-party firewall product or turn on the Microsoft Windows Internet Connection Firewall.
To turn on the Windows Firewall in Windows Vista
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Click Start, and click Control Panel.
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Click Security.
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Click Turn Windows Firewall on or off.
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Select On.
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Click OK.
To turn on the Internet Connection Firewall in Windows XP
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Click Start, and click Control Panel.
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Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
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Click Change Windows Firewall Settings.
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Select On.
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Click OK.
Get the latest computer updates
Updates help protect your computer from viruses, worms, and other threats as they are discovered. It is important to install updates for all the software that is installed in your computer. These are usually available from vendor websites.
You can use the Automatic Updates feature in Windows to automatically download future Microsoft security updates while your computer is on and connected to the Internet.
To turn on Automatic Updates in Windows Vista
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Click Start, and click Control Panel.
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Click System and Maintainance.
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Click Windows Updates.
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Select a setting. Microsoft recommends selecting Install updates automatically and choose a time that is convenient for you. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
To turn on Automatic Updates in Windows XP
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Click Start, and click Control Panel.
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Click System.
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Click Automatic Updates.
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Select a setting. Microsoft recommends selecting Automatic. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
Use up-to-date antivirus software
Most antivirus software can detect and prevent infection by known malicious software. To help protect you from infection, you should always run antivirus software that is updated with the latest signature files. Antivirus software is available from several sources. For more information,
see http://www.microsoft.com/protect/computer/viruses/vista.mspx.
Use caution when opening attachments and accepting file transfers
Exercise caution with e-mail and attachments received from unknown sources, or received unexpectedly from known sources. Use extreme caution when accepting file transfers from known or unknown sources.
Use caution when clicking on links to web pages
Exercise caution with links to web pages that you receive from unknown sources, especially if the links are to a web page that you are not familiar with or are suspicious of. Malicious software may be installed in your system simply by visiting a web page with harmful content.
Avoid downloading pirated software
Threats may also be bundled with software and files that are available for download on various torrent sites. Downloading "cracked" or "pirated" software from these sites carries not only the risk of being infected with malware, but is also illegal. For more information. please see our article '
The risks of obtaining and using pirated software'.
Protect yourself from social engineering attacks
While attackers may attempt to exploit vulnerabilities in hardware or software in order to compromise a system, they also attempt to exploit vulnerabilities in human behavior in order to do the same. When an attacker attempts to take advantage of human behavior in order to persuade the affected user to perform an action of the attacker's choice, it is known as 'social engineering'. Essentially, social engineering is an attack against the human interface of the targeted system. For more information, please see our article '
What is social engineering?'.
