ID:9783 - Exploit for Cryptographic issues in PuTTY - CVE-2024-31497

Link to public exploit:

Vulnerability description

The vulnerability allows a remote attacker to recover NIST P-521 private keys.

The vulnerability exists due to the PuTTY client and all related components generate heavily biased ECDSA nonces in the case of NIST P-521. A remote attacker can recover the NIST P-521 private key using roughly 60 valid ECDSA signatures generated by any PuTTY component under the same key.

Note, if the key has been used to sign arbitrary data (e.g., git commits by forwarding Pageant to a development host), the publicly available signatures (e.g., on GitHub) can be used as well.

Remediation