This indicates an attack attempt against an Information Disclosure vulnerability in Microsoft Internet Explorer.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted HTML file. An attacker can exploit this by tricking an unsuspecting user into visiting a malicious webpage on vulnerable systems and obtain sensitive information.
Internet Explorer 9
Internet Explorer 10
Internet Explorer 11
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems
Apply the most recent upgrade or patch from the vendor.