Threat behavior
Backdoor:Win32/IRCBot!5320 is a backdoor Trojans that targets computers running Microsoft Windows. The Trojan drops other malicious software and opens a backdoor on the infected computer to connect to IRC servers. The Trojan can maintain multiple IRC server connections simultaneously to receive commands from attackers.
When Backdoor:Win32/IRCBot!5320 is executed, it performs the following actions:
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Drops these files into the <system folder>
intlprinters.exe
libcintle2.dll
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Creates registry entries to run Backdoor:Win32/IRCBot!5320 when Windows restarts:
Adds value: printers
With data: {30f78bba-f385-4cf9-8ef3-039fae793cc1}
In subkey:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\ShellServiceObjectDelayLoad
Adds value: (default)
With data: "libcintle2.dll"
In subkey:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{30F78BBA-F385-4CF9-8EF3-039FAE793CC1}\InProcServer32
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Injects code from the dropped dll to these processes
explorer.exe
cmd.exe
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Connects to a remote IRC server using TCP port 80 in order to allow connections from remote attackers, and to execute commands sent by a remote attacker
Backdoor:Win32/IRCBot!5320 may be detected as Backdoor:Win32/IRCbot.OU.
Prevention
Take the following steps to help prevent infection on your system:
Enable a firewall on your computer.
Get the latest computer updates.
Use up-to-date antivirus software.
Use caution with attachments and file transfers.
Enable a firewall on your computer
Use a third-party firewall product or turn on the Microsoft Windows XP Internet Connection Firewall.
To turn on the Internet Connection Firewall in Windows XP
Click Start, and click Control Panel.
Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
Click Change Windows Firewall Settings.
Select On.
Click OK.
Get the latest computer updates
Updates help protect your computer from viruses, worms, and other threats as they are discovered. You can use the Automatic Updates feature in Windows XP to automatically download future Microsoft security updates while your computer is on and connected to the Internet.
To turn on Automatic Updates in Windows XP
Click Start, and click Control Panel.
Click System.
Click Automatic Updates.
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/athome/security/downloads/default.mspx
Use caution with attachments and 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.
