This indicates an attempt to exploit a memory access vulnerability in the OpenSSL server.
The OpenSSL server in a vulnerable system does not properly validate the server name extension received in the 'Hello' packet from a Client. A remote attacker could send a specially crafted 'Hello' packet, which contains \x00 as server name extension, to the OpenSSL server on a vulnerable system. This will cause a memory access error in the OpenSSL server, leading to a crash and a denial of service.
Impact
Denial of Service: Remote attackers can crash vulnerable systems.