A vulnerability has been discovered in KVIrc, which can be exploited by malicious people to hijack IRC connections.

The vulnerability is caused due to the application not properly handling carriage return ("\r") characters when processing CTCP requests. This can be exploited to e.g. inject carriage return characters into KVIrc's failed DCC handshake notification, which can be used to e.g. execute IRC commands in the context of the user's IRC session.

Successful exploitation requires that the "boolNotifyFailedDccHandshakes" option is enabled (default).

The vulnerability is confirmed in version 4.0.0 for Windows. Other versions may also be affected.

Solution
Update to version 4.0.2.

Provided and/or discovered by
unic0rn

Changelog
Further details available to Secunia VIM customers

Original Advisory
https://svn.kvirc.de/kvirc/ticket/858
http://www.kvirc.net/?id=news&story=2010.08.01.16.30.1.story&dir=latest&lang=en

Alternate/detailed remediation
Further details available in Customer Area

Deep Links
Links available to Secunia VIM customers