USN-4504-1: OpenSSL vulnerabilities

16 September 2020

Several security issues were fixed in OpenSSL.

Releases

Packages

  • openssl - Secure Socket Layer (SSL) cryptographic library and tools
  • openssl1.0 - Secure Socket Layer (SSL) cryptographic library and tools

Details

Robert Merget, Marcus Brinkmann, Nimrod Aviram, and Juraj Somorovsky
discovered that certain Diffie-Hellman ciphersuites in the TLS
specification and implemented by OpenSSL contained a flaw. A remote
attacker could possibly use this issue to eavesdrop on encrypted
communications. This was fixed in this update by removing the insecure
ciphersuites from OpenSSL. (CVE-2020-1968)

Cesar Pereida GarcĂ­a, Sohaib ul Hassan, Nicola Tuveri, Iaroslav Gridin,
Alejandro Cabrera Aldaya, and Billy Brumley discovered that OpenSSL
incorrectly handled ECDSA signatures. An attacker could possibly use this
issue to perform a timing side-channel attack and recover private ECDSA
keys. This issue only affected Ubuntu 18.04 LTS. (CVE-2019-1547)

Guido Vranken discovered that OpenSSL incorrectly performed the x86_64
Montgomery squaring procedure. While unlikely, a remote attacker could
possibly use this issue to recover private keys. This issue only affected
Ubuntu 18.04 LTS. (CVE-2019-1551)

Bernd Edlinger discovered that OpenSSL incorrectly handled certain
decryption functions. In certain scenarios, a remote attacker could
possibly use this issue to perform a padding oracle attack and decrypt
traffic. This issue only affected Ubuntu 18.04 LTS. (CVE-2019-1563)

Update instructions

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

Ubuntu 18.04
Ubuntu 16.04

After a standard system update you need to reboot your computer to make
all the necessary changes.

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