This indicates an attack attempt to exploit a Denial of Service vulnerability in LAN Messenger.
The vulnerability is due to an error when the vulnerable software handles an overly long string in an initiation request. A remote attacker may be able to exploit this to cause a denial of service condition on the affected system.
LAN Messenger 1.2.28 and earlier versions
Denial of Service: Remote attackers can crash vulnerable systems.
Currently we are unaware of any vendor supplied patch or updates available for this issue.