USN-3999-1: GnuTLS vulnerabilities

30 May 2019

gnutls28 vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 19.04
  • Ubuntu 18.10
  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 LTS

Summary

Several security issues were fixed in GnuTLS.

Software Description

  • gnutls28 - GNU TLS library

Details

Eyal Ronen, Kenneth G. Paterson, and Adi Shamir discovered that GnuTLS was vulnerable to a timing side-channel attack known as the "Lucky Thirteen" issue. A remote attacker could possibly use this issue to perform plaintext-recovery attacks via analysis of timing data. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2018-10844, CVE-2018-10845, CVE-2018-10846)

Tavis Ormandy discovered that GnuTLS incorrectly handled memory when verifying certain X.509 certificates. A remote attacker could use this issue to cause GnuTLS to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 18.04 LTS, Ubuntu 18.10, and Ubuntu 19.04. (CVE-2019-3829)

It was discovered that GnuTLS incorrectly handled certain post-handshake messages. A remote attacker could use this issue to cause GnuTLS to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 18.10 and Ubuntu 19.04. (CVE-2019-3836)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 19.04
libgnutls30 - 3.6.5-2ubuntu1.1
Ubuntu 18.10
libgnutls30 - 3.6.4-2ubuntu1.2
Ubuntu 18.04 LTS
libgnutls30 - 3.5.18-1ubuntu1.1
Ubuntu 16.04 LTS
libgnutls30 - 3.4.10-4ubuntu1.5

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

In general, a standard system update will make all the necessary changes.

References