User-provided inputs must be sanitized before they are logged. An attacker can use unsanitized input to break a log's integrity, forge log entries, or bypass log monitors.
1def logging_noncompliant():
2 filename = input("Enter a filename: ")
3 # Noncompliant: unsanitized input is logged.
4 logger.info("Processing %s", filename)
1def logging_compliant():
2 filename = input("Enter a filename: ")
3 if filename.isalnum():
4 # Compliant: input is validated before logging.
5 logger.info("Processing %s", filename)