CVE-2019-11841
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.
| Software | From | Fixed in |
|---|---|---|
| golang / crypto | 2019-03-25 | 2019-03-25.x |
| debian / debian_linux | 8.0 | 8.0.x |
| debian / debian_linux | 9.0 | 9.0.x |
- http://packetstormsecurity.com/files/152840/Go-Cryptography-Libraries-Cleartext-Message-Spoofing.html
- https://go.googlesource.com/crypto/
- https://lists.debian.org/debian-lts-announce/2019/09/msg00011.html
- https://lists.debian.org/debian-lts-announce/2020/10/msg00014.html
- https://lists.debian.org/debian-lts-announce/2023/06/msg00017.html
- https://sec-consult.com/
- https://sec-consult.com/en/blog/advisories/cleartext-message-spoofing-in-go-cryptography-libraries-cve-2019-11841/
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A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
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