USN-3675-1: GnuPG vulnerabilities

11 June 2018

gnupg, gnupg2 vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 18.04 LTS
  • Ubuntu 17.10
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS

Summary

Several security issues were fixed in GnuPG.

Software Description

  • gnupg2 - GNU privacy guard - a free PGP replacement
  • gnupg - GNU privacy guard - a free PGP replacement

Details

Marcus Brinkmann discovered that during decryption or verification, GnuPG did not properly filter out terminal sequences when reporting the original filename. An attacker could use this to specially craft a file that would cause an application parsing GnuPG output to incorrectly interpret the status of the cryptographic operation reported by GnuPG. (CVE-2018-12020)

Lance Vick discovered that GnuPG did not enforce configurations where key certification required an offline master Certify key. An attacker with access to a signing subkey could generate certifications that appeared to be valid. This issue only affected Ubuntu 18.04 LTS. (CVE-2018-9234)

Update instructions

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

Ubuntu 18.04 LTS
gnupg - 2.2.4-1ubuntu1.1
gpg - 2.2.4-1ubuntu1.1
Ubuntu 17.10
gnupg - 2.1.15-1ubuntu8.1
Ubuntu 16.04 LTS
gnupg - 1.4.20-1ubuntu3.2
Ubuntu 14.04 LTS
gnupg - 1.4.16-1ubuntu2.5

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

In general, a standard system update will make all the necessary changes.

References