[AJECT] WinGate Email Server (IMAP) vulnerability

[João Antunes <jantunes () di fc ul pt>]

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Synopsis
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WinGate is vulnerable to denial-of-service (DoS) attacks caused  
probably by a resource exhaustion vulnerability.
The IMAP server ceases to provide access to its clients after  
processing a LIST command with a large parameter (see details bellow).

Product: WinGate
Version: 6.2.2 and probably the older versions
Vendor: Qbik (www.wingate.com)
Type: Denial-of-service
Risk: service disruption
Remote: Yes
Discovered by: João Antunes (AJECT -- Attack Injection Tool) on 14/May/ 
2008
Exploit: Not Available
Solution: Not Available
Status: Developers were contacted several times since the  
vulnerability was discovered.


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Vulnerability Description
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The vulnerability can be triggered by sending the following messages  
to the imap server:
A01 LOGIN <user> <password>
A02 LIST Ax1000 *

Depending on the server's resources, it may be required to repeat the  
above exploit to deplete its resources. (in a 512MB RAM configuration,  
the exploit was executed twice)
The above exploit caused the server to reject all subsequent  
connections with a "NO access denied" reply thus resulting in a remote  
denial of service.