This report was translated by AI; nobody has reviewed the translation yet. Original language: Czech.
[TLP:CLEAR] PuTTY 0.81 and derivatives fix a vulnerability allowing private key disclosure
The PuTTY SSH client version 0.81 fixes a serious vulnerability in the signing with ECDSA keys using the NIST P-521 elliptic curve. This vulnerability was also fixed in FileZilla 3.67.0, WinSCP 6.3.3 and TortoiseGit 2.15.0.1. Users should consider all NIST P-521 keys used with PuTTY to be compromised and should immediately remove them from authorized entries and other platforms [1].
An attacker with access to several dozen signed messages and the public key can recover the private key and then forge signatures. This allows them to log in to any servers for which the key is used. To obtain the necessary signatures, it is enough for the attacker to gain control of any server where this key is used for authentication, or to temporarily gain access to the Pageant program in which the key is stored [1][2].
The vulnerability is present in product:
- PuTTY; >=0.68, <=0.80
CVSS: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
More information:
- CVE-2024-31497 at cve.org, NVD
- CWE-310 at cwe.mitre.org
The vulnerability was publicly disclosed 15. 4. 2024.
Links
By CESNET, z.s.p.o. Michaela Jarošová on 17. 4. 2024.