GnuPG: Incorrect signature verification
Gentoo Linux Security Advisory
||GLSA 200602-10 / gnupg
||February 18, 2006
||February 18, 2006: 01
All supported architectures
Applications relying on GnuPG to authenticate digital signatures may
incorrectly believe a signature has been verified.
GnuPG (The GNU Privacy Guard) is a free replacement for PGP
(Pretty Good Privacy). As GnuPG does not rely on any patented
algorithms, it can be used without any restrictions. gpgv is the
OpenPGP signature verification tool provided by the GnuPG system.
Tavis Ormandy of the Gentoo Linux Security Auditing Team
discovered that automated systems relying on the return code of GnuPG
or gpgv to authenticate digital signatures may be misled by malformed
signatures. GnuPG documentation states that a return code of zero (0)
indicates success, however gpg and gpgv may also return zero if no
signature data was found in a detached signature file.
An attacker may be able to bypass authentication in automated
systems relying on the return code of gpg or gpgv to authenticate
There is no known workaround at this time.
All GnuPG users should upgrade to the latest version:
Code Listing 3.1: Resolution
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-crypt/gnupg-18.104.22.168"