Ubuntu 20.04 LTS USN-4738-1 Moderate: OpenSSL DoS Risk Fix

ubuntu

February 18, 2021

Several security issues were fixed in OpenSSL.

Summary

Several security issues were fixed in OpenSSL.

Software Description:

- openssl: Secure Socket Layer (SSL) cryptographic library and tools

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

Details:

Paul Kehrer discovered that OpenSSL incorrectly handled certain input

lengths in EVP functions. A remote attacker could possibly use this issue

to cause OpenSSL to crash, resulting in a denial of service.

(CVE-2021-23840)

Tavis Ormandy discovered that OpenSSL incorrectly handled parsing issuer

fields. A remote attacker could possibly use this issue to cause OpenSSL to

crash, resulting in a denial of service. (CVE-2021-23841)

Topics Covered

security advisory moderate denial of service security issue update update instructions ubuntu openssl

Update Instructions

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

Ubuntu 20.10:
  libssl1.1                       1.1.1f-1ubuntu4.2

Ubuntu 20.04 LTS:
  libssl1.1                       1.1.1f-1ubuntu2.2

Ubuntu 18.04 LTS:
  libssl1.0.0                     1.0.2n-1ubuntu5.6
  libssl1.1                       1.1.1-1ubuntu2.1~18.04.8

Ubuntu 16.04 LTS:
  libssl1.0.0                     1.0.2g-1ubuntu4.19

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