Autor:
Security Flaw with Digital signatures in Microsoft Outlook -
Emails in Microsoft Outlook digitally signed with S/MIME using either a commercial personal
certificate like Verisign or using a certificate issued by MS
Certificate Server can be altered. Outlook will not show any warnings
about the email being changed, the digital signature will still be
reported valid even though the message content has been modified and
parties involved in the signatures changed.
This is an extremely serious flaw as I can change any digitally signed
emails I want without Outlook ever noticing.