CVE-2019-11841

Published: 22 May 2019

A message-forgery issue was discovered in crypto/openpgp/clearsign/clearsign.go in supplementary Go cryptography libraries 2019-03-25. According to the OpenPGP Message Format specification in RFC 4880 chapter 7, a cleartext signed message can contain one or more optional "Hash" Armor Headers. The "Hash" Armor Header specifies the message digest algorithm(s) used for the signature. However, the Go clearsign package ignores the value of this header, which allows an attacker to spoof it. Consequently, an attacker can lead a victim to believe the signature was generated using a different message digest algorithm than what was actually used. Moreover, since the library skips Armor Header parsing in general, an attacker can not only embed arbitrary Armor Headers, but also prepend arbitrary text to cleartext messages without invalidating the signatures.

Priority

Medium

CVSS 3 base score: 5.9

Status

Package Release Status
golang-go.crypto
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 20.10 (Groovy Gorilla) Not vulnerable
(1:0.0~git20200221.2aa609c-1)
Ubuntu 20.04 LTS (Focal Fossa) Not vulnerable
(1:0.0~git20200221.2aa609c-1)
Ubuntu 18.04 LTS (Bionic Beaver) Needed

Ubuntu 16.04 LTS (Xenial Xerus) Needed

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

Ubuntu 12.04 ESM (Precise Pangolin) Does not exist

Patches:
Upstream: https://go.googlesource.com/crypto/+/c05e17bb3b2dca130fc919668a96b4bec9eb9442
snapd
Launchpad, Ubuntu, Debian
Upstream Not vulnerable
(code-not-present)
Ubuntu 20.10 (Groovy Gorilla) Not vulnerable
(code-not-present)
Ubuntu 20.04 LTS (Focal Fossa) Not vulnerable
(code-not-present)
Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable
(code-not-present)
Ubuntu 16.04 LTS (Xenial Xerus) Not vulnerable
(code-not-present)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

Ubuntu 12.04 ESM (Precise Pangolin) Does not exist