This indicates an attack attempt against a Denial of Sevice vulnerability in Microsoft .NET implementation of XML Digital Signatures.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted PFX file. A remote attacker may be able to exploit this to execute arbitrary code within the context of the application, via a crafted PFX file.
All versions of Windows
Denial of Service: Remote attackers can crash vulnerable systems.
Currently we are unaware of any vendor supplied patch for this issue.