CyberArk's Credential Provider loopback communications on TCP port 18923 are encrypted with key material that has extremely low entropy. In all currently-known use cases, the effective key space is less than 2^16. For an attacker who understands the key derivation scheme and encryption mechanics, knowledge of the source port and access to the payloads of a given client-server exchange are sufficient to reduce effective key space to one. In cases where the source port is not known, the encrypted payloads will be unable to withstand a brute force attack. Additionally, the user identification mechanism used by CyberArk's Credential Provider is vulnerable to a race condition where an unauthorized/unprivileged user can submit one or more encrypted query requests. If the race is won, the attacker will be able to retrieve sensitive information including passwords and password metadata. Versions before 12.1 are affected.
Vulmon