Description: A vulnerability has been reported in SSH Secure Shell and SSH Sentinel, which can be exploited by malicious people to cause a DoS (Denial of Service) on a vulnerable system.
The vulnerability is caused due to an error in the BER/DER decoding. This can be exploited by sending malformed BER/DER packets to a vulnerable system, which may cause it to crash.
Servers are vulnerable if:
* Certificate based authentication is used with the "Pki" definition in the configuration file.
* Hostbased authentication for the server and the client is used.
* The commercial or non-commercial version of the SSH Secure Shell Client for Windows is used.
Server are not vulnerable if:
* Only password authentication is used.
* The non-commercial Unix distribution that does not contain the PKI functionality is used.
* Public key authentication is allowed without specifying the "Pki" keyword in the server configuration file (sshd2_config).
Solution: Update to SSH Secure Shell version 3.2.9 or SSH Sentinel version 1.4.1 build 98.
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