Sysax Multi-Server <= 6.10 SSHD Key Exchange DoS

Vulnerability Description

A denial-of-service vulnerability exists in Sysax Multi-Server version 6.10 via its SSH daemon. A specially crafted SSH key exchange packet can trigger a crash in the service, resulting in loss of availability. The flaw is triggered during the handling of malformed key exchange data, including a non-standard byte (\x28) in place of the expected SSH protocol delimiter.

References

• https://www.mattandreko.com/2013/04/08/sysax-multi-server-6.10-ssh-dos/
• https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/auxiliary/dos/windows/ssh/sysax_sshd_kexchange.rb
• https://www.sysax.com/
• https://www.vulncheck.com/advisories/sysax-multi-server-sshd-key-exchange-dos