Out-of-support Control-M/Agent versions 9.0.18 to 9.0.20 (and potentially earlier unsupported versions) that are configured to use the non-default Blowfish cryptography algorithm use a hardcoded key. An attacker with access to network traffic and to this key could decrypt network traffic between the Control-M/Agent and Server.
The product uses a hard-coded, unchangeable cryptographic key.