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Ubuntu Security Notice USN-3339-1
June 22, 2017

openvpn vulnerabilities
==========================================================================

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

- Ubuntu 17.04
- Ubuntu 16.10
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in OpenVPN.

Software Description:
- openvpn: virtual private network software

Details:

Karthikeyan Bhargavan and GaA<<tan Leurent discovered that 64-bit block
ciphers are vulnerable to a birthday attack. A remote attacker could
possibly use this issue to recover cleartext data. Fixing this issue
requires a configuration change to switch to a different cipher. This
update adds a warning to the log file when a 64-bit block cipher is in use.
This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS and
Ubuntu 16.10. (CVE-2016-6329)

It was discovered that OpenVPN incorrectly handled rollover of packet ids.
An authenticated remote attacker could use this issue to cause OpenVPN to
crash, resulting in a denial of service. This issue only affected Ubuntu
14.04 LTS, Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2017-7479)

Guido Vranken discovered that OpenVPN incorrectly handled certain malformed
IPv6 packets. A remote attacker could use this issue to cause OpenVPN to
crash, resulting in a denial of service. (CVE-2017-7508)

Guido Vranken discovered that OpenVPN incorrectly handled memory. A remote
attacker could use this issue to cause OpenVPN to crash, resulting in a
denial of service. (CVE-2017-7512)

Guido Vranken discovered that OpenVPN incorrectly handled an HTTP proxy
with NTLM authentication. A remote attacker could use this issue to cause
OpenVPN clients to crash, resulting in a denial of service, or possibly
expose sensitive memory contents. (CVE-2017-7520)

Guido Vranken discovered that OpenVPN incorrectly handled certain x509
extensions. A remote attacker could use this issue to cause OpenVPN to
crash, resulting in a denial of service. (CVE-2017-7521)

Update instructions:

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

Ubuntu 17.04:
  openvpn                         2.4.0-4ubuntu1.3

Ubuntu 16.10:
  openvpn                         2.3.11-1ubuntu2.1

Ubuntu 16.04 LTS:
  openvpn                         2.3.10-1ubuntu2.1

Ubuntu 14.04 LTS:
  openvpn                         2.3.2-7ubuntu3.2

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

References:
  https://www.ubuntu.com/usn/usn-3339-1
  CVE-2016-6329, CVE-2017-7479, CVE-2017-7508, CVE-2017-7512,
  CVE-2017-7520, CVE-2017-7521

Package Information:
  https://launchpad.net/ubuntu/+source/openvpn/2.4.0-4ubuntu1.3
  https://launchpad.net/ubuntu/+source/openvpn/2.3.11-1ubuntu2.1
  https://launchpad.net/ubuntu/+source/openvpn/2.3.10-1ubuntu2.1
  https://launchpad.net/ubuntu/+source/openvpn/2.3.2-7ubuntu3.2