USN-3183-2: GnuTLS vulnerability

Ubuntu Security Notice USN-3183-2

20th March, 2017

gnutls26 vulnerability

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

  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS

Summary

GnuTLS could be made to hang if it received specially crafted network traffic.

Software description

  • gnutls26 - GNU TLS library

Details

USN-3183-1 fixed CVE-2016-8610 in GnuTLS in Ubuntu 16.04 LTS and Ubuntu
16.10. This update provides the corresponding update for Ubuntu 12.04 LTS
and Ubuntu 14.04 LTS.

Original advisory details:

Stefan Buehler discovered that GnuTLS incorrectly verified the serial
length of OCSP responses. A remote attacker could possibly use this issue
to bypass certain certificate validation measures. This issue only applied
to Ubuntu 16.04 LTS. (CVE-2016-7444)

Shi Lei discovered that GnuTLS incorrectly handled certain warning alerts.
A remote attacker could possibly use this issue to cause GnuTLS to hang,
resulting in a denial of service. This issue has only been addressed in
Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2016-8610)

It was discovered that GnuTLS incorrectly decoded X.509 certificates with a
Proxy Certificate Information extension. 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 16.04 LTS
and Ubuntu 16.10. (CVE-2017-5334)

It was discovered that GnuTLS incorrectly handled certain OpenPGP
certificates. A remote attacker could possibly use this issue to cause
GnuTLS to crash, resulting in a denial of service, or possibly execute
arbitrary code. (CVE-2017-5335, CVE-2017-5336, CVE-2017-5337)

Update instructions

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

Ubuntu 14.04 LTS:
libgnutls26 2.12.23-12ubuntu2.7
Ubuntu 12.04 LTS:
libgnutls26 2.12.14-5ubuntu3.14

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

CVE-2016-8610