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HydraIRC - DCC Denial Of Service

Portcullis Security Advisory      07_008

Vulnerable System: 


Vulnerability Title:  

Denial of service due to format string vulnerability in DCC file transfer 

Vulnerability Discovery and Development: 

Portcullis Security Testing Services

Credit for Discovery

Nico Leidecker of Portcullis Computer Security Ltd discovered this 
vulnerability. Further research was then carried out.

Vendor Status: 

The vendor has been informed and the vulnerability has been fixed.

Affected systems: 

Version 0.3.151 was tested to be vulnerable.


HydraIRC is an IRC client supporting DCC file transfers. The client is prone 
to a format string vulnerability as it passes user input to a function 
expecting a format string. This only occurs, when the DCC file transfer 
negotiation fails.


By sending a special crafted DCC file transfer request to the victim, an
attacker is then able to conduct a Denial of Service attack against them.


Proof of concept exploit code is available.

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