GnuPG: Incorrect signature verification
Gentoo Linux Security Advisory
||GLSA 200603-08 / gnupg
||March 10, 2006
||March 10, 2006: 01
All supported architectures
GnuPG may erroneously report a modified or unsigned message has a valid
The GNU Privacy Guard, GnuPG, is a free replacement for the PGP
suite of cryptographic software that may be used without restriction,
as it does not rely on any patented algorithms. GnuPG can be used to
digitally sign messages, a method of ensuring the authenticity of a
message using public key cryptography.
OpenPGP is the standard that defines the format of digital
signatures supported by GnuPG. OpenPGP signatures consist of multiple
sections, in a strictly defined order. Tavis Ormandy of the Gentoo
Linux Security Audit Team discovered that certain illegal signature
formats could allow signed data to be modified without detection. GnuPG
has previously attempted to be lenient when processing malformed or
legacy signature formats, but this has now been found to be insecure.
A remote attacker may be able to construct or modify a
digitally-signed message, potentially allowing them to bypass
authentication systems, or impersonate another user.
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-126.96.36.199"