Arch Linux Security Advisory ASA-201609-25

Severity: Medium
Date : 2016-09-26
CVE-ID : CVE-2016-7444
Package : gnutls
Type : certificate verification bypass
Remote : Yes
Link : https://wiki.archlinux.org/index.php/CVE

Summary

The package gnutls before version 3.4.15-1 is vulnerable to certificate
verification bypass.

Resolution

Upgrade to 3.4.15-1.

pacman -Syu “gnutls>=3.4.15-1”

The problem has been fixed upstream in version 3.4.15.

Workaround

None.

Description

Incorrect length validation on gnutls’s gnutls_ocsp_resp_check_crt
method can allow an attacker to use a OCSP response for a different
certificate (but from the same CA) to continue using a revoked
certificate. This can happen if the serial from the revoked certificate
is a prefix of the other one, and the additional bytes happen to be
equal on the system doing the verification.

Impact

A remote attacker is able to bypass certificate verification and
continue using a revoked certificate under certain circumstances.

References

https://lists.gnupg.org/pipermail/gnutls-devel/2016-September/008146.html
https://gitlab.com/gnutls/gnutls/commit/964632f37dfdfb914ebc5e49db4fa29af35b1de9
https://access.redhat.com/security/cve/CVE-2016-7444