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.
CVE-2019-11841 - Medium Severity Vulnerability
[mirror] Go supplementary cryptography libraries
Library home page: https://proxy.golang.org/github.com/golang/crypto/@v/v0.0.0-20171018132924-ed5229da99e3.zip
Dependency Hierarchy: - :x: **github.com/golang/crypto-v0.0.0-20171018132924-ed5229da99e3** (Vulnerable Library)
Found in HEAD commit: 9505f4ca92405cc9273dc3726c2d274ce28a4407
Found in base branch: ALL_HANDS/major-secrets
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.
Publish Date: 2019-05-22
URL: CVE-2019-11841
Base Score Metrics: - Exploitability Metrics: - Attack Vector: Network - Attack Complexity: High - Privileges Required: None - User Interaction: None - Scope: Unchanged - Impact Metrics: - Confidentiality Impact: None - Integrity Impact: High - Availability Impact: None
For more information on CVSS3 Scores, click here.Type: Upgrade version
Origin: https://nvd.nist.gov/vuln/detail/CVE-2019-11841
Release Date: 2019-05-22
Fix Resolution: golang-golang-x-crypto-dev - 1:0.0~git20200221.2aa609c-1,1:0.0~git20170407.0.55a552f+REALLY.0.0~git20161012.0.5f31782-1+deb8u1,1:0.0~git20200221.2aa609c-1;golang-go.crypto-dev - 1:0.0~git20170407.0.55a552f+REALLY.0.0~git20161012.0.5f31782-1+deb8u1,1:0.0~git20200221.2aa609c-1,1:0.0~git20200221.2aa609c-1
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