This indicates an attack attempt against a buffer overflow vulnerability in HP OpenView Network Node Manager.
The vulnerability is caused by an error when the vulnerable software handles a malicious "header" or "cookie". It allows a remote attacker to execute arbitrary code via sending a crafted web page.
HP OpenView Network Node Manager 7.01
HP OpenView Network Node Manager 7.51
HP OpenView Network Node Manager 7.53
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the patch, available from the following web site: