This indicates an attack attempt against an Information Disclosure vulnerability in Microsoft Internet Explorer.
The vulnerability is due to insufficient sanitizing of user supplied inputs in the application. A remote attacker can exploit this to gain unauthorized access to sensitive information.
Microsoft Internet Explorer 8
Microsoft Internet Explorer 9
Microsoft Internet Explorer 10
Microsoft Internet Explorer 11
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Apply the most recent upgrade or patch from the vendor.