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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.

Notes

AuthorNote
jdstrand
snapd contains an embedded copy of golang-go.crypto
the version of golang-go.crypto that is embedded does not contain
the clearsign package. Nothing in the source uses the clearsign APIs
Priority

Medium

CVSS 3 base score: 5.9

Status

Package Release Status
golang-go.crypto
Launchpad, Ubuntu, Debian
bionic Needed

cosmic Ignored
(reached end-of-life)
disco Ignored
(reached end-of-life)
eoan Ignored
(reached end-of-life)
focal Not vulnerable
(1:0.0~git20200221.2aa609c-1)
groovy Not vulnerable
(1:0.0~git20200221.2aa609c-1)
hirsute Not vulnerable
(1:0.0~git20200221.2aa609c-1)
impish Not vulnerable
(1:0.0~git20200221.2aa609c-1)
jammy Not vulnerable
(1:0.0~git20200221.2aa609c-1)
kinetic Not vulnerable
(1:0.0~git20200221.2aa609c-1)
precise Does not exist

trusty Does not exist

upstream Needs triage

xenial Needed

Patches:
upstream: https://go.googlesource.com/crypto/+/c05e17bb3b2dca130fc919668a96b4bec9eb9442
snapd
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(code-not-present)
cosmic Not vulnerable
(code-not-present)
disco Not vulnerable
(code-not-present)
eoan Not vulnerable
(code-not-present)
focal Not vulnerable
(code-not-present)
groovy Not vulnerable
(code-not-present)
hirsute Not vulnerable
(code-not-present)
impish Not vulnerable
(code-not-present)
jammy Not vulnerable
(code-not-present)
kinetic Not vulnerable
(code-not-present)
precise Does not exist

trusty Does not exist

upstream Not vulnerable
(code-not-present)
xenial Not vulnerable
(code-not-present)