This indicates an attack attempt against an Information Disclosure vulnerability in Internet Explorer.
The vulnerability is caused by Internet Explorer not properly restricting access to the clipboard of a user who visits a website. An attacker could collect information from the clipboard of a user if that user visits the malicious site.
Internet Explorer 6
Internet Explorer 7
Internet Explorer 8
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.