Several security issues were fixed in OpenVPN.
Karthikeyan Bhargavan and Gaëtan 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)
22 June 2017
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in OpenVPN.
Karthikeyan Bhargavan and Gaëtan 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)
The problem can be corrected by updating your system to the following package versions:
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.
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