Tailgating and Badge-Only Entries in a Shared Mantrap
A multi-tenant colocation has a shared entrance mantrap serving 12 cages. Entry requires a badge and a fingerprint, but the inner door uses a request-to-exit push button and releases automatically on fire alarm. In the last quarter, logs show 14 tailgating incidents, one inner door held open for 95 seconds, and three entries using a badge at 03:00 that had no matching biometric event. The alarm delay for a held door is set to 120 seconds. CCTV covers the mantrap but not the cage fronts. A tenant has complained that its auditor found no evidence of anti-passback. The landlord wants to add turnstiles, but the fire consultant says they would reduce egress width below the required two exits. The site is staffed 24/7 by one security officer who also handles remote hands requests.
1. Assess the access-control weaknesses and prioritize them by risk. Which findings are most likely to indicate a security breach rather than poor usability?
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Highest risk is the badge entry at 03:00 with no matching biometric event. That can mean a forced or propped door, a bypassed reader, an integration failure, or a badge shared with someone who did not authenticate. It is more serious than ordinary tailgating because the audit trail is incomplete. The 95-second held door and 120-second alarm delay are also significant: the alarm is too slow to catch a deliberate hold, and the request-to-exit button lets one person open the inner door for several others. The 14 tailgating incidents indicate a design and culture problem. Priorities: (1) validate badge-biometric binding and anti-passback at both doors; (2) shorten held-door alarm and investigate all three 03:00 events; (3) add CCTV coverage of cage fronts and mantrap interlock; (4) enforce one-person-per-entry and escort rules. Turnstiles are not the first fix and may conflict with egress.
2. Recommend a layered mitigation plan that respects fire egress and multi-tenant lease constraints.
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Respect fire egress: keep fail-safe release on fire alarm, crash bars, and the required clear width; do not install turnstiles that reduce egress below the two-exit requirement. In the mantrap, use interlocking doors with anti-passback, badge plus biometric at entry, and a request-to-exit sensor rather than a freely pressed button where code allows. Set held-door alarms to a short delay, for example 15-30 seconds, with local sounder and camera call-up. Add camera coverage of the mantrap and cage fronts in common areas, with privacy notices and lease-compliant placement. For 12 tenants, enforce cage-level locks, visitor escort, and tenant-specific access schedules; give the security officer a clear response procedure and remote monitoring backup. Review lease language before adding cameras or biometrics. The goal is layered control: prevention, detection, delay, and audit.
3. What tests and metrics would you use to prove the controls work after implementation?
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Run a 30-day baseline and post-change comparison: tailgating incidents per 1,000 entries, held-door alarms, anti-passback exceptions, badge-only entries, biometric failure rate, and mean time for the officer to respond. Test the fire-alarm release of every controlled door and verify egress width and hardware. Conduct a penetration test that attempts piggybacking, door holding, and credential sharing, and review audit logs for completeness and retention. Confirm that camera coverage records the cage fronts and mantrap with usable image quality. Set thresholds for escalation, for example any badge-only entry is investigated same day, and report results to the tenant auditor. Re-test after any firmware or integration change. Metrics should demonstrate both security and life safety, not just that the system is installed.