This indicates an attack attempt against a Cross-Site Scripting vulnerability in AlienVault OSSIM.
The vulnerability is due to insufficient validation of user supplied data in the application. A remote attacker can exploit this by tricking an unsuspecting user into visiting a malicious webpage and execute arbitrary script code within the context of the target user's browser.
AlienVault OSSIM 5.2 and older versions
AlienVault USM 5.2 and older versions
System Compromise: Remote attackers can execute arbitrary script code within the context of the target user's browser
Apply the most recent upgrade or patch from the vendor.