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CVE-2024-31497 Detail


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, and TortoiseSVN through 1.14.6.


CVSS 4.0 Severity and Metrics:

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://www.openwall.com/lists/oss-security/2024/04/15/6 Mailing List  Third Party Advisory 
https://bugzilla.redhat.com/show_bug.cgi?id=2275183 Issue Tracking 
https://bugzilla.suse.com/show_bug.cgi?id=1222864 Issue Tracking 
https://docs.ccv.brown.edu/oscar/connecting-to-oscar/ssh/ssh-agent-forwarding/key-generation-and-agent-forwarding-with-putty Product 
https://filezilla-project.org/versions.php Release Notes 
https://git.tartarus.org/?h=c193fe9848f50a88a4089aac647fecc31ae96d27&p=simon/putty.git Mailing List  Patch 
https://github.com/advisories/GHSA-6p4c-r453-8743 Third Party Advisory 
https://github.com/daedalus/BreakingECDSAwithLLL Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IZS3B37GNGWOOV7QU7B7JFK76U4TOP4V/ Mailing List  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MMHILY2K7HQGQRHOC375KRRG2M6625RD/ Mailing List  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PUOTQVGC4DISVHQGSPUYGXO6TLDK65LA/ Mailing List  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WFDZBV7ZCAZ6AH3VCQ34SSY7L3J7VZXZ/ Mailing List  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WMJH7M663BVO3SY6MFAW2FAZWLLXAPRQ/ Mailing List  Third Party Advisory 
https://news.ycombinator.com/item?id=40044665 Issue Tracking 
https://security-tracker.debian.org/tracker/CVE-2024-31497 Third Party Advisory 
https://securityonline.info/cve-2024-31497-critical-putty-vulnerability-exposes-private-keys-immediate-action-required/ Press/Media Coverage 
https://tartarus.org/~simon/putty-snapshots/htmldoc/Chapter9.html#pageant-forward Product 
https://tortoisegit.org Third Party Advisory 
https://twitter.com/CCBalert/status/1780229237569470549 Press/Media Coverage 
https://twitter.com/lambdafu/status/1779969509522133272 Press/Media Coverage 
https://winscp.net/eng/news.php Third Party Advisory 
https://www.bleepingcomputer.com/news/security/putty-ssh-client-flaw-allows-recovery-of-cryptographic-private-keys/ Press/Media Coverage 
https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html Release Notes  Vendor Advisory 
https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-p521-bias.html Vendor Advisory 
https://www.openwall.com/lists/oss-security/2024/04/15/6 Mailing List  Third Party Advisory 
https://www.reddit.com/r/sysadmin/comments/1c4wmoj/putty_vulnerability_affecting_v068_to_v08/ Press/Media Coverage 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) cwe source acceptance level NIST  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

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Quick Info

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