PGP Desktop 10.0.3 and earlier versions as well as 10.1.0 are vulnerable to an unsigned data injection attack. PGP Command Line versions 9.6 and greater are not affected by this vulnerability.
The PGP Desktop user interface incorrectly displays messages with unsigned data as signed. A user will not be able to distinguish the legitimate signed part from the malicious unsigned parts. Additional details may be found in PGP's KnowledgeBase article 2290, Symantec's Security Advisory SYM10-012, and Eric R. Verheul's Pretty Good Piggy-backing paper.
An attacker could add a message part (attachment) to a valid, signed PGP message and the entire message, including the attacker's message part, would be reported to the reader as having a valid signature.
Apply an Update
Users should upgrade to version 10.0.3 SP2 or 10.1.0 SP1.
PGP recommends the following workaround:
If you use PGP Desktop for Windows, do not use the Decrypt & Verify shortcut menu available when you right-click an OpenPGP message file. Instead, launch PGP Desktop, select File->Open, browse to the file name, and open the file. Alternately, double-click the file icon to have it opened in PGP Desktop automatically.
Vendor| Status| Date Notified| Date Updated
Symantec| | 14 Nov 2010| 18 Nov 2010
If you are a vendor and your product is affected, let us know.
Group | Score | Vector
Base | N/A | N/A
Temporal | N/A | N/A
Environmental | N/A | N/A
Thanks to Eric R. Verheul for reporting this vulnerability.
This document was written by Jared Allar.