Widely-Used PuTTY SSH Client Found Vulnerable to Key Recovery Attack
Apr 16, 2024
Encryption / Network Security
The maintainers of the PuTTY Secure Shell (SSH) and Telnet client are alerting users of a critical vulnerability impacting versions from 0.68 through 0.80 that could be exploited to achieve full recovery of NIST P-521 (ecdsa-sha2-nistp521) private keys. The flaw has been assigned the CVE identifier CVE-2024-31497 , with the discovery credited to researchers Fabian Bäumer and Marcus Brinkmann from the Ruhr University Bochum. "The effect of the vulnerability is to compromise the private key," the PuTTY project said in an advisory. "An attacker in possession of a few dozen signed messages and the public key has enough information to recover the private key, and then forge signatures as if they were from you, allowing them to (for instance) log in to any servers you use that key for." However, in order to obtain the signatures, an attacker will have to compromise the server for which the key is used to authenticate to. In a message posted on the Open Sou...
