CVE-2018-10844

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.

The updated packages fix security vulnerabilities:

It was found that the GnuTLS implementation of HMAC-SHA-256 and HMAC-SHA-384 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 (CVE-2018-10844, CVE-2018-10845).

A cache-based side channel in GnuTLS implementation that leads to plain text recovery in cross-VM attack setting was found. An attacker could use a combination of "Just in Time" Prime+probe attack in combination with Lucky-13 attack to recover plain text using crafted packets (CVE-2018-10846).

This update for gnutls fixes the following issues:

This update for gnutls fixes the following issues:

Security issues fixed:

• Improved mitigations against Lucky 13 class of attacks
• 'Just in Time' PRIME + PROBE cache-based side channel attack can lead to plaintext recovery (CVE-2018-10846, bsc#1105460)
• HMAC-SHA-384 vulnerable to Lucky thirteen attack due to use of wrong constant (CVE-2018-10845, bsc#1105459)
• HMAC-SHA-256 vulnerable to Lucky thirteen attack due to not enough dummy function calls (CVE-2018-10844, bsc#1105437)
• The _asn1_check_identifier function in Libtasn1 caused a NULL pointer dereference and crash (CVE-2017-10790, bsc#1047002)

This update for gnutls fixes the following issues:

This update for gnutls fixes the following issues:

Security issues fixed:

• Improved mitigations against Lucky 13 class of attacks
• 'Just in Time' PRIME + PROBE cache-based side channel attack can lead to plaintext recovery (CVE-2018-10846, bsc#1105460)
• HMAC-SHA-384 vulnerable to Lucky thirteen attack due to use of wrong constant (CVE-2018-10845, bsc#1105459)
• HMAC-SHA-256 vulnerable to Lucky thirteen attack due to not enough dummy function calls (CVE-2018-10844, bsc#1105437)
• The _asn1_check_identifier function in Libtasn1 caused a NULL pointer dereference and crash (CVE-2017-10790, bsc#1047002)

This update for gnutls fixes the following issues:

Security issues fixed:

• Improved mitigations against Lucky 13 class of attacks
  • 'Just in Time' PRIME + PROBE cache-based side channel attack can lead to plaintext recovery (CVE-2018-10846, bsc#1105460)
  • HMAC-SHA-384 vulnerable to Lucky thirteen attack due to use of wrong constant (CVE-2018-10845, bsc#1105459)
  • HMAC-SHA-256 vulnerable to Lucky thirteen attack due to not enough dummy function calls (CVE-2018-10844, bsc#1105437)
• The _asn1_check_identifier function in Libtasn1 caused a NULL pointer dereference and crash (CVE-2017-10790, bsc#1047002)

This update for gnutls fixes the following security issues:

• Improved mitigations against Lucky 13 class of attacks
• CVE-2018-10846: 'Just in Time' PRIME + PROBE cache-based side channel attack can lead to plaintext recovery (bsc#1105460)
• CVE-2018-10845: HMAC-SHA-384 vulnerable to Lucky thirteen attack due to use of wrong constant (bsc#1105459)
• CVE-2018-10844: HMAC-SHA-256 vulnerable to Lucky thirteen attack due to not enough dummy function calls (bsc#1105437)
• CVE-2017-10790: The _asn1_check_identifier function in Libtasn1 caused a NULL pointer dereference and crash (bsc#1047002)

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)