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Troubleshooting Snort

Troubleshooting Snort

This page is primarily for the team. It's public so that you can learn from it. For help using, see the user docs.


Snort is a network intrusion detection system that runs on all hosts.

Responding to snort alerts

  • Identify the rule that triggered the alert. Snort alerts include a snort rule ID (sid), such as 1:22968. Check for a description of the alert rule and its impact and mitigations.
  • Check the snort logs to verify that the alert is a true positive.

    • Connect to the host identified in the error message.
    • Inspect the snort logs:

      cat /var/vcap/sys/log/snort-eth0/snort.log.XXXXX | strings
    • Optionally use u2spewfoo to decode the snort binary format:

      /var/vcap/packages/snort/bin/u2spewfoo /var/vcap/sys/log/snort-eth0/snort.log.XXXXX
  • If the alert appears to be a false positive, consider excluding the rule from the snort configuration.

  • If the alert appears to be a true positive, read about mitigations and apply if appropriate.