Redact opaque auth/security config blobs in FTDC metadata

[zelmario]

Problem

The FTDC metadata document (getCmdLineOpts / setParameter, plus similar config dumps in logs) carries opaque config blobs whose values embed sensitive infrastructure detail the existing masking can't reach:

• oidcIdentityProviders — a stringified JSON array with the OIDC issuer, tenant, audience, clientId
• auditLog / auditFilter — audit config embedding users, hosts, app names
• ldapServers / ldapQueryUser / ldapBindDN, kmip*, saslauthdPath, clusterIpSource(Allow|White)list

The obfuscator walks and masks FTDC metadata by key, but these values are opaque blobs (often stringified JSON), so an unknown key holding the blob passes through untouched — and a single-label internal hostname inside it has no FQDN/IP/email signal for value-based detection either.

Real-world trigger: an FTDC ticket leaked a Kubernetes hostname, an Azure AD tenant, an OIDC issuer, and audit usernames straight through, all buried in these blobs.

Fix

Redact these keys' values wholesale (SENSITIVE_CONFIG_KEYS → "<redacted-config>") inside _obfuscate_bson_doc.

These are configuration, not metrics, so no FTDC diagnostic value is lost — the numeric setParameter tuning the analysis relies on (e.g. storageEngineConcurrentWriteTransactions) lives under different keys and is preserved. Verified: the blobs redact, embedded host/tenant/issuer/usernames are gone, FTDC still decodes, and the concurrency metric survives.

Scope

Small and self-contained (19 insertions, 1 line if→elif): only _obfuscate_bson_doc changes, gated on the new key set. Independent of #1, #2, #3.

[gitguardian]

⚠️ GitGuardian has uncovered 1 secret following the scan of your pull request.

Please consider investigating the findings and remediating the incidents. Failure to do so may lead to compromising the associated services or software components.

🔎 Detected hardcoded secret in your pull request

GitGuardian id	GitGuardian status	Secret	Commit	Filename
34213448	Triggered	Generic Password	3e65b90	mongodb_obfuscator.py	View secret

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