# CVE-2024-31497: Weak cryptography in n/a > Biased ECDSA nonce generation in PuTTY allows attackers to recover private keys from signatures, enabling unauthorized access and supply-chain attacks. - **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 15 Apr 2024 - **Updated:** 4 Nov 2025 - **Also known as:** ALPINE-CVE-2024-31497, DEBIAN-CVE-2024-31497, DLA-3839-1, GHSA-6p4c-r453-8743, MGASA-2024-0140, UBUNTU-CVE-2024-31497, openSUSE-SU-2024:0111-1, openSUSE-SU-2024:13868-1, openSUSE-SU-2024:13870-1 ## What is CVE-2024-31497? CVE-2024-31497 is a medium-severity vulnerability in Fedoraproject Fedora, published on 15 Apr 2024. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6. Weakness: CWE-338 (Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)) ## Which versions are affected by CVE-2024-31497? It affects 6 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `putty` | SUSE:Package Hub 15 SP5 | All versions | 0.81-bp155.2.6.1 | | `putty` | openSUSE:Leap 15.5 | All versions | 0.81-bp155.2.6.1 | | `filezilla` | openSUSE:Tumbleweed | All versions | 3.67.0-1.1 | | `putty` | openSUSE:Tumbleweed | All versions | 0.81-1.1 | Products: Fedoraproject Fedora, Filezilla-Project Filezilla Client, Putty Putty, Tigris Tortoisesvn, Tortoisegit Tortoisegit, Winscp Winscp. ## How do I fix CVE-2024-31497? Upgrade to a fixed version. ## Is CVE-2024-31497 being exploited? There is no known exploitation of CVE-2024-31497 in the wild and no public exploit code. Public exploit code: - Proof Of Concept that exploits PuTTy CVE-2024-31497. (github_poc): https://github.com/HugoBond/CVE-2024-31497-POC - https://github.com/edutko/cve-2024-31497 (github_poc): https://github.com/edutko/cve-2024-31497 - A script designed to uncover vulnerabilities in Putty by exploiting CVE-2024-31497. (github_poc): https://github.com/sh1k4ku/CVE-2024-31497 - https://github.com/LukaWynants/Onderzoek_CVE-2024-31497-POC (github_poc): https://github.com/LukaWynants/Onderzoek_CVE-2024-31497-POC ## Other vulnerabilities in Fedoraproject Fedora - [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild) - [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild) - [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2024-31497 and fix it if it is affected. What it is: CVE-2024-31497 is a medium-severity vulnerability in Fedoraproject Fedora, published on 15 Apr 2024. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2024-31497 in the wild and no public exploit code. Affected product: Fedoraproject Fedora. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2024-31497/ (Markdown: https://insights.sbomify.com/CVE-2024-31497/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2024-31497 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-31497 - OSV: https://osv.dev/vulnerability/CVE-2024-31497 --- From sbomify Insights: https://insights.sbomify.com/CVE-2024-31497/ Summaries are generated and may contain mistakes; the official description above is the record.