Vulnerability Disclosure

If you have any security concerns regarding Security Onion or believe you have uncovered a vulnerability, please send an email to per the following guidelines:

  • Include a description of the issue and steps to reproduce

  • Use plain text format in the email (no Word documents or PDF files)

Please do NOT disclose publicly until we have had sufficient time to resolve the issue.


This security address should be used only for undisclosed vulnerabilities. Dealing with fixed issues or general questions on how to use Security Onion should be handled via the normal Support channels.

Product and Supply Chain Integrity

Security Onion is based on free and open software. Third-party components, as well as the software that the Security Onion team develops, is built from source code that is readily available for the public to review. Community contributors, or anyone for that matter, can request to have notifications pushed to them when a change is accepted into the public repositories. This is very different from closed source software since those closed source code bases are only visible to a very small group of developers. Further, if a closed source code base does not have formal code review procedures in place, or lacks infrastructure around the code base to make others aware of new changes, this further restricts visibility and review of changes. These deficiencies allow attackers that gain unauthorized access to a closed source code base to make changes without others detecting it.

When upstream, third-party components are updated in Security Onion, the change requires multiple checks before it can be merged into the master (released) branch. First, all commits must be signed using cryptography before being allowed into the master branch. Second, code reviews and approvals from multiple team members are required before the pull requests can be merged. Both of these restrictions are enforced by the source code repository itself, which eliminates risk of a human mistake allowing the process to be bypassed. Further, changes to the Security Onion source code repositories cause notifications to be delivered to the Security Onion development team, as well as anyone in the public who choose to be notified of such changes. On top of this, Security Onion developers are required (enforced by the repository itself) to use multi-factor authentication in order to approve changes.

Additionally, Security Onion’s build infrastructure runs both unit level tests and fully automated end-to-end tests on every release, to ensure the Security Onion platform, and its components, continue to operate as expected. When a change is merged into Security Onion, whether it’s to upgrade an upstream component or a modification to the source code maintained by the Security Onion developers, which breaks the automated tests, we are notified and take action to review the failure and root cause. Often this results in our developers chasing down upstream code commits to find out why something changed, and if it was intended or not. Fortunately, these investigations are typically bug related, rather than malicious, and our team will either contribute a pull request to fix the upstream project, or file an issue to raise awareness to the project maintainers.

There is no guarantee that any software, open or closed source, will always be free from attacks. However, our commitment to open software, and our investments into repeatable processes and software automation and testing technologies improves Security Onion’s posture when it comes to safe guarding the product and its user-base.