Ubuntu Security Notice 3675-1 - 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. 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. Various other issues were also addressed.
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Ubuntu Security Notice USN-3675-1
June 11, 2018
gnupg, gnupg2 vulnerabilities
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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
In general, a standard system update will make all the necessary changes.
References:
https://usn.ubuntu.com/usn/usn-3675-1
CVE-2018-12020, CVE-2018-9234
Package Information:
https://launchpad.net/ubuntu/+source/gnupg2/2.2.4-1ubuntu1.1
https://launchpad.net/ubuntu/+source/gnupg2/2.1.15-1ubuntu8.1
https://launchpad.net/ubuntu/+source/gnupg/1.4.20-1ubuntu3.2
https://launchpad.net/ubuntu/+source/gnupg/1.4.16-1ubuntu2.5