ASA-202006-2: gnutls: man-in-the-middle
Arch Linux Security Advisory ASA-202006-2
========================================
Severity: High
Date : 2020-06-06
CVE-ID : CVE-2020-13777
Package : gnutls
Type : man-in-the-middle
Remote : Yes
Link : https://security.archlinux.org/AVG-1177
Summary
======
The package gnutls before version 3.6.14-1 is vulnerable to man-in-the-
middle.
Resolution
=========
Upgrade to 3.6.14-1.
# pacman -Syu "gnutls>=3.6.14-1"
The problem has been fixed upstream in version 3.6.14.
Workaround
=========
None.
Description
==========
GnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a
session ticket (a loss of confidentiality in TLS 1.2, and an
authentication bypass in TLS 1.3). The earliest affected version is
3.6.4 (2018-09-24) because of an error in a 2018-09-18 commit. Until
the first key rotation, the TLS server always uses wrong data in place
of an encryption key derived from an application.
Impact
=====
A remote attacker can man-in-the-middle a connection to bypass
authentication in TLS 1.3, and recover previous conversations in TLS
1.2.
References
=========
https://gnutls.org/security-new.html#GNUTLS-SA-2020-06-03
https://gitlab.com/gnutls/gnutls/-/issues/1011
https://gitlab.com/gnutls/gnutls/-/commit/c2646aeee94e71cb15c90a3147cf3b5b0ca158ca?merge_request_iid75
https://security.archlinux.org/CVE-2020-13777
A gnutls security update has been released for Arch Linux to address a man-in-the-middle issue.
