Sequoia OpenPGP Remote Denial-of-Service Vulnerability via Crafted Encrypted Message

A denial-of-service vulnerability has been identified in Sequoia OpenPGP versions prior to 2.1.0. The issue arises in the 'aes_key_unwrap' function, which panics when it receives a ciphertext that is too short. This behavior can be exploited by a remote attacker who sends an encrypted message with a modified PKESK or SKESK packet, causing the application to crash when the message is decrypted.

Impact

Exploitation of this vulnerability leads to a crash of the application processing the crafted encrypted message.

Reproduction

The vulnerability can be reproduced by sending an encrypted message with a PKESK or SKESK packet that has been intentionally modified to create a short ciphertext. When the recipient application attempts to decrypt the message, it will encounter a panic due to the underflow, causing the application to crash.

Remediation

Users can upgrade to Sequoia OpenPGP version 2.1.0 or later to address this vulnerability.