Microsoft has released a new security patch for Outlook 2002:

Flaw in how Outlook 2002 handles V1 Exchange Server Security Certificates could lead to Information

Microsoft Outlook 2002 provides the facility to encrypt e-mails sent between e-mail recipients. Encryption is used to prevent parties other than the intended recipients from reading the contents of an e-mail. Outlook uses public key certificates to facilitate the exchange of the cryptographic keys that are used in the encryption process, and Outlook offers a number of different options as to what type of certificates can be used. S/MIME certificates are the most commonly used (and are not affected by the vulnerability that is the subject of this bulletin), but there are other certificate options including V1 Exchange Server Security certificates.

A vulnerability exists because there is a flaw in the way Outlook
2002 handles a V1 Exchange Server Security certificate when using it to encrypt e-mail. As a result of this flaw, Outlook fails to encrypt the mail correctly and the message will be sent in plain text. This could cause the information in the e-mail to be exposed when the user believed it to be protected through encryption.

Read more