Re: PGPsdk Key Validity Vulnerability

[Florian Weimer <Florian.Weimer () RUS Uni-Stuttgart DE>]

Patrick Oonk <patrick () pine nl> writes:

> A vulnerability in PGP's display of key validity has been discovered
> that could allow an attacker to fool users into thinking that a valid
> signature was created by what is actually an invalid user ID.

According to Sieuwert van Otterloo, PGP 5 and 6 are affected by this
problem as well.  (However, these versions have other problems as
well, so you should not use them anyway.)

Similar problems exist in PGP 2.x (the PGP version by Phil's Pretty
Good Software) and its derivatives.  Their notion of the primary user
ID is flawed, too, although they do not support the V4 primary user ID
subpacket.

GnuPG does not mark non-certified user IDs when listing the user IDs
for a key (but at least lists all user IDs, so you can notice that
something fishy is going on), and the use of '--with-colons' without
'--fixed-list-mode' by a frontend might cause the frontend to output
misleading information much in the same way as PGP 7.

-- 
Florian Weimer                    Florian.Weimer () RUS Uni-Stuttgart DE
University of Stuttgart           http://cert.uni-stuttgart.de/
RUS-CERT                          +49-711-685-5973/fax +49-711-685-5898