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This CVE record has been updated after NVD enrichment efforts were completed. Enrichment data supplied by the NVD may require amendment due to these changes.
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.
Metrics
NVD enrichment efforts reference publicly available information to associate
vector strings. CVSS information contributed by other sources is also
displayed.
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https://github.com/advisories/GHSA-6p4c-r453-8743 No Types Assigned
https://github.com/advisories/GHSA-6p4c-r453-8743 Third Party Advisory
Changed
Reference Type
https://github.com/daedalus/BreakingECDSAwithLLL No Types Assigned
https://github.com/daedalus/BreakingECDSAwithLLL Third Party Advisory
Changed
Reference Type
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IZS3B37GNGWOOV7QU7B7JFK76U4TOP4V/ No Types Assigned
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IZS3B37GNGWOOV7QU7B7JFK76U4TOP4V/ Mailing List, Third Party Advisory
Changed
Reference Type
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MMHILY2K7HQGQRHOC375KRRG2M6625RD/ No Types Assigned
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MMHILY2K7HQGQRHOC375KRRG2M6625RD/ Mailing List, Third Party Advisory
Changed
Reference Type
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PUOTQVGC4DISVHQGSPUYGXO6TLDK65LA/ No Types Assigned
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PUOTQVGC4DISVHQGSPUYGXO6TLDK65LA/ Mailing List, Third Party Advisory
Changed
Reference Type
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WFDZBV7ZCAZ6AH3VCQ34SSY7L3J7VZXZ/ No Types Assigned
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WFDZBV7ZCAZ6AH3VCQ34SSY7L3J7VZXZ/ Mailing List, Third Party Advisory
Changed
Reference Type
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WMJH7M663BVO3SY6MFAW2FAZWLLXAPRQ/ No Types Assigned
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WMJH7M663BVO3SY6MFAW2FAZWLLXAPRQ/ Mailing List, Third Party Advisory
Changed
Reference Type
https://news.ycombinator.com/item?id=40044665 No Types Assigned
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. One 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. Because SSH is sometimes used to authenticate to Git services, it is possible that this vulnerability could be leveraged for supply-chain attacks on software maintained in Git. It is also conceivable that signed messages from PuTTY or Pageant are readable by adversaries more easily in other scenarios, but none have yet been disclosed.
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.
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. One 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. Because SSH is sometimes used to authenticate to Git services, it is possible that this vulnerability could be leveraged for supply-chain attacks on software maintained in Git. It is also conceivable that signed messages from PuTTY or Pageant are readable by adversaries more easily in other scenarios, but none have yet been disclosed.
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