CVE-2023-4680: 
HashiCorp Vault vulnerability analysis and mitigation

CVE-2023-4680 affects HashiCorp Vault and Vault Enterprise's transit secrets engine, introduced in version 1.6.0 and fixed in versions 1.14.3, 1.13.7, and 1.12.11. The vulnerability allowed authorized users to specify arbitrary nonces even with convergent encryption disabled (HashiCorp Advisory).

The vulnerability exists in the transit secrets engine's encrypt endpoint, which provides encryption and decryption operations using Vault-managed keys. The system failed to restrict user-provided nonces during encryption operations when convergent encryption was disabled. The vulnerability has a CVSS v3.1 Base Score of 6.8 (Medium) with vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N (NVD).

An authenticated user with authorization to encrypt transit data could potentially decrypt arbitrary ciphertext by performing encryption operations using known plaintexts and nonces. Additionally, for non-convergent modes using AES-GCM, authorized users could potentially derive the authentication subkey used to authenticate the ciphertext (HashiCorp Advisory).

Organizations should upgrade to Vault versions 1.14.3, 1.13.7, 1.12.11, or newer to address this vulnerability. HashiCorp recommends evaluating the risk and consulting their documentation for guidance on transit key rotation and version-specific upgrade notes (HashiCorp Advisory).

The vulnerability was responsibly disclosed by Rob Zimmerman and Sze Chuen Tan of Cloudflare to HashiCorp, demonstrating effective security collaboration between organizations (HashiCorp Advisory).