Revision Note: V1.4 (July 29, 2014): Revised advisory to announce that Microsoft no longer plans to enforce the stricter verification behavior as a default functionality on supported releases of Microsoft Windows. It remains available as an opt-in feature. See the Advisory FAQ section for more information.
Summary: Microsoft is announcing the availability of an update for all supported releases of Microsoft Windows to change how signatures are verified for binaries signed with the Windows Authenticode signature format. The change is included with Security Bulletin MS13-098, but will only be enabled on an opt-in basis. When enabled, the new default behavior for Windows Authenticode signature verification will no longer allow extraneous information in the WIN_CERTIFICATE structure, and Windows will no longer recognize non-compliant binaries as signed.