Security News > 2024 > April > PuTTY SSH client flaw allows recovery of cryptographic private keys
A vulnerability tracked as CVE-2024-31497 in PuTTY 0.68 through 0.80 could potentially allow attackers with access to 60 cryptographic signatures to recover the private key used for their generation.
PuTTY is a popular open-source terminal emulator, serial console, and network file transfer application that supports SSH, Telnet, SCP, and SFTP. System administrators and developers predominantly use the software to remotely access and manage servers and other networked devices over SSH from a Windows-based client.
The main repercussion of recovering the private key is that it allows unauthorized access to SSH servers or sign commits as the developer.
Brinkmann explained on X that attackers require 58 signatures to calculate a target's private key, which they can acquire either by collecting them from logins to an SSH server they control or is compromised, or from signed Git commits.
One such case is the use of SSH keys for signing Git commits.
It is noted that any P521 private keys generated using the vulnerable version of the tool should be considered unsafe and replaced by new, secure keys.
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Related Vulnerability
| DATE | CVE | VULNERABILITY TITLE | RISK |
|---|---|---|---|
| 2024-04-15 | CVE-2024-31497 | Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) vulnerability in multiple products 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. | 5.9 |