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             AUSCERT External Security Bulletin Redistribution

                    USN-3999-1: GnuTLS vulnerabilities
                                31 May 2019


        AusCERT Security Bulletin Summary

Product:           GnuTLS
Publisher:         Ubuntu
Operating System:  Ubuntu
Impact/Access:     Access Privileged Data -- Remote/Unauthenticated
                   Denial of Service      -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-3836 CVE-2019-3829 CVE-2018-10846
                   CVE-2018-10845 CVE-2018-10844 

Reference:         ESB-2019.1477

Original Bulletin: 

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USN-3999-1: GnuTLS vulnerabilities
30 May 2019

gnutls28 vulnerabilities
A security issue affects these releases of Ubuntu and its derivatives:

  o Ubuntu 19.04
  o Ubuntu 18.10
  o Ubuntu 18.04 LTS
  o Ubuntu 16.04 LTS


Several security issues were fixed in GnuTLS.

Software Description

  o gnutls28 - GNU TLS library


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

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.


  o CVE-2018-10844
  o CVE-2018-10845
  o CVE-2018-10846
  o CVE-2019-3829
  o CVE-2019-3836

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