Affected: [UNKNOWN] gnutls

It was found that the GnuTLS implementation of HMAC-SHA-256 was vulnerable to a Lucky thirteen style attack. Remote attackers could use this flaw to conduct distinguishing attacks and plaintext-recovery attacks via statistical analysis of timing data using crafted packets.

Affected: Ubuntu:16.04:LTS: gnutls28, Ubuntu:18.04:LTS: gnutls28

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)