Missing audit log entries for failed authentication attempts

[hman38705]

Labels: security, observability, api

Priority: Medium

Description

src/audit_middleware.rs captures audit events for admin operations but does not log failed authentication attempts. Without this, brute-force attacks against the API are invisible in the audit trail.

Acceptance Criteria

• Add audit log entries for authentication failures (invalid API key, expired token, missing credentials)
• Include the attempted key prefix (first 4 chars, masked), client IP, and user agent in the failure record
• Add a Prometheus counter auth_failures_total with labels for failure reason
• Add a test that verifies a 401 response produces an audit log entry

[temisan0x]

@temisan0x has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi Maintainer! I'd love to take on this issue

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[extolkom]

@extolkom has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Please assign me

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[mohadon0]

@mohadon0 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this issue

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[Caneryy]

@Caneryy has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi, I'd like to work on this issue please.

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[drips-wave]

Congratulations, @mohadon0! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @mohadon0: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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