A system of client devices and a server system implementing services makes use of credentials to facilitate authentication of the client devices with the server and generates log entries for different accesses to the server system. A monitoring system places credentials and log entries referencing the monitoring system with the credentials and log entries on the client devices without any authentication or actual access attempts by the client devices to the monitoring system. Unauthorized access to the client devices may result in the credentials and log entries to the monitoring system being accessed and used to access the monitoring system. Attempts to exploit the monitoring system using the credentials and log entries is contained within the monitoring system and data is collected to characterize malicious code attempting to exploit the monitoring system. The data is then used to prevent attacks and detect compromised client devices and server systems.