Bug 1222864 (CVE-2024-31497) - VUL-0: CVE-2024-31497: putty: NIST P521 private keys are exposed by biased signature generation
Summary: VUL-0: CVE-2024-31497: putty: NIST P521 private keys are exposed by biased si...
Status: RESOLVED FIXED
: 1225350 (view as bug list)
Alias: CVE-2024-31497
Product: openSUSE Distribution
Classification: openSUSE
Component: Security (show other bugs)
Version: Leap 15.5
Hardware: Other Other
: P3 - Medium : Normal (vote)
Target Milestone: ---
Assignee: Jan Engelhardt
QA Contact: Security Team bot
URL: https://smash.suse.de/issue/401933/
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Depends on:
Blocks:
 
Reported: 2024-04-15 21:29 UTC by Andreas Stieger
Modified: 2024-05-27 16:36 UTC (History)
1 user (show)

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Marketing QA Status: ---
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Description Andreas Stieger 2024-04-15 21:29:46 UTC
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 lattice-based 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. 

https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-p521-bias.html
https://www.openwall.com/lists/oss-security/2024/04/15/6
https://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=c193fe9848f50a88a4089aac647fecc31ae96d27
Comment 1 Marcus Meissner 2024-04-16 07:22:14 UTC
filezilla bug opened at bug 1222871
Comment 2 OBSbugzilla Bot 2024-04-16 16:05:02 UTC
This is an autogenerated message for OBS integration:
This bug (1222864) was mentioned in
https://build.opensuse.org/request/show/1168380 Backports:SLE-15-SP5 / putty
Comment 3 Andreas Stieger 2024-05-27 16:35:37 UTC
*** Bug 1225350 has been marked as a duplicate of this bug. ***
Comment 4 Andreas Stieger 2024-05-27 16:36:22 UTC
Fixed in 15.5. 
15.6: https://build.opensuse.org/request/show/1177124