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             AUSCERT External Security Bulletin Redistribution

                    USN-4504-1: OpenSSL vulnerabilities
                             17 September 2020


        AusCERT Security Bulletin Summary

Product:           OpenSSL
Publisher:         Ubuntu
Operating System:  Ubuntu
Impact/Access:     Access Privileged Data   -- Remote/Unauthenticated
                   Access Confidential Data -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-1968 CVE-2019-1563 CVE-2019-1551

Reference:         ESB-2020.2383

Original Bulletin: 

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USN-4504-1: OpenSSL vulnerabilities
16 September 2020

Several security issues were fixed in OpenSSL.

  o Ubuntu 18.04 LTS
  o Ubuntu 16.04 LTS


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


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 Garcia, 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

Ubuntu 18.04

  o libssl1.0.0 - 1.0.2n-1ubuntu5.4

Ubuntu 16.04

  o libssl1.0.0 - 1.0.2g-1ubuntu4.17

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


  o CVE-2019-1547
  o CVE-2019-1551
  o CVE-2019-1563
  o CVE-2020-1968

Related notices

  o USN-4376-1 : libssl1.0.0, libssl1.1, openssl
  o USN-4376-2 : libssl1.0.0, openssl

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