This indicates a possible attempt to exploit a Cross Domain Verification vulnerability in Internet Explorer 5.5 and 6.0.
The vulnerability allows remote attackers to bypass the cross-domain security model and access information on the local system or in other domains, and possibly execute code.
Microsoft Internet Explorer 6.0 SP1 and earlier versions.
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Apply the IE cumulative patch from MS02-066.