T 3.27 Improper time synchronisation

If the system time is not properly synchronised on IT systems, each system will use another time. This may result in problems of proper functioning or availability of the system.

The following problems may occur:

• Significant deviations of time between the IT systems may result in disturbance, delay and impossibility of communication between the systems due to deviating time stamps in the messages.
• An event covering all areas, e.g. distribution of malicious software via the network or a port scan performed in the network, leaves traces on the individual systems (log entries, file access) with highly deviating time stamps. This massively impedes clarification of the event because the traces cannot be properly combined.
• When clearing computer crime the value of computer-based proofs can be highly limited if the correctness of the system time cannot be verified.
• In case of time-based services such as licence servers or OCSP (Online Certificate Status Protocol) responders, an incorrect system time may result in malfunction of the service, e.g. because licences or certificates are deemed to be expired.
• If the time source of a network using a single reference procedure for time synchronisation fails, there will be no second reference time available. This may result in uncontrolled change of file and object rights.