Werk #12672: real-time-checks: Provide default password
| Component | Checks & agents | ||||
| Title | real-time-checks: Provide default password | ||||
| Date | Apr 1, 2021 | ||||
| Level | Trivial Change | ||||
| Class | Security Fix | ||||
| Compatibility | Compatible - no manual interaction needed | ||||
| Checkmk versions & editions |
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This Werk fixes a security issue that may arise from a misconfiguration of real-time checks.
As mentioned in Werk #8350
(Introduction of real-time checks), a password has to be provided when
configuring real-time checks.
When using the agent bakery, the ruleset "Encryption" is used to
provide the encryption password, while the real-time checks itself are
activated for the agents via the ruleset "Send data for real-time checks".
If the real-time checks get activated without providing a password, this
will result in an empty password, that will nevertheless be used by the agent
to encrypt the real-time check data on the host.
While the user would most likely fix this situation, because real-time checks
won't work (A password is mandatory to activate real-time checks in CMC),
the real-time check data can be decrypted without a password/key in this case,
resulting in a security issue.
This is now fixed with the following mechanism:
- The agent bakery will read the default password from the global setting "Monitoring core/Enable handling of real-time checks" and bake it into the agents that have the rule "Send data for real-time checks" activated. Accordingly, a changed global setting will lead to new agents on next bake.
- The agent bakery will keep to package the password from the "Encryption" rule, and the Linux agent will prefer it over the default password from the CMC configuration.
- If none of the two passwords are configured, but the "Send data for real-time checks" rule is active, the agent bakery will refuse to bake agents.
- If the Linux agent is requested to send encrypted real-time check data, but no password is deployed, the sending be inhibited. However, up from now, this may only happen if real-time checks are configured without the agent bakery.