This indicates an attack attempt against a Denial Of Service vulnerability in SSH1 protocol implementation in OpenSSH.
The vulnerability is caused by improper implementation of a function in the kex module. A remote attacker may be able to exploit this to cause a denial of service condition on affected systems.
OpenSSH OpenSSH prior to revision 1.127
OpenSSH OpenSSH portable prior to version 7.4p1
Denial of Service: Remote attackers can crash vulnerable systems.
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