Physical Security: The Forgotten Perimeter (And Why It’s Still Critical)

We’ve all heard the horror stories of stolen laptops, propped-open fire doors, and wayward tailgaters slipping past “secure” entrances. In our rush to lock down networks and data with the latest encryption keys and zero-trust frameworks, it’s easy to overlook good old-fashioned physical security. But as offices open back up—or operate in a hybrid mode—physical security remains a cornerstone of any serious cybersecurity strategy.

Why Physical Security Still Matters

Physical security is about protecting your buildings, assets, and people from real-world threats—unauthorised access, environmental damage, theft, or even sabotage. The simplest breach I’ve seen involved an attacker shoulder-surfing a distracted employee’s login credentials. No advanced malware required—just a keen eye at the right time. That’s how quickly physical lapses can unravel even the strongest digital defences.

The Complacency Trap: Shared Responsibility vs. 100% Liability

One of my biggest criticisms of physical security is that when we’re responsible for our own safety—like at home—we’re switched on. We’ll double-check locked doors, question unexpected visitors, and stay on high alert for anything unusual. Yet the moment we step into the workplace, we tend to relax, assuming “security has it covered.” This mindset is dangerous.

Yes, the organisation shoulders the ultimate liability if something goes wrong. However, employees still share accountability for upholding security measures day to day. It’s well within an employer’s right to expect everyone—management, staff, and visitors—to stay vigilant. If even one person props open a door or neglects to challenge an unfamiliar face, the entire security posture crumbles.

Key Components of a Modern Physical Security Strategy

• Locks and Keys
  You’d be amazed how often the basics are overlooked. A fire door propped open with an ashtray is a goldmine for someone looking to slip inside. Regular checks and staff education go a long way. Simply making sure locked doors swing shut I hate to say would even be a good start!
• Biometric and Mobile-Based Systems
  Traditional biometrics (fingerprints, facial recognition) continue to evolve. Some companies now use mobile-based access control with digital credentials on smartphones. Either way, avoid outdated systems with known exploits. A flipper zero is surprisingly effective at bypassing unencrypted electronic locks.
• Badges, Cards & Beyond
  RFID badges can be cloned with the right tools. Modern card technology has come along way, old ones can be breached new ones not so much. If a badge is lost, deactivate it immediately. I once saw a breach stem from a stolen contractor card, no registry and no visibility on signed out cards.

• CCTV & Intelligent Analytics
  Cameras aren’t just to catch who steals the last donut. AI-driven surveillance can alert you in real time to suspicious behaviour, like someone lingering by a locked door. If you invest in cameras, have a plan for monitoring and responding to alerts.
• Motion Sensors
  Perfect for after-hours monitoring or low-traffic areas. Even basic sensors can provide a big advantage in detecting unauthorized activity when no one’s around.

• Perimeter Basics
  Even large enterprises can benefit from clear boundaries, whether that’s strategic fencing, well-defined property lines, or card-access gates in parking areas. Simple measures like trimming back hedges near entrances reduce hiding spots for opportunistic intruders.
• Security Lighting
  A well-lit site is a key deterrent to unauthorised entry and helps employees feel safer—especially when hybrid schedules mean people might come and go at off-peak hours. Ensuring parking lots, walkways, and side entrances are illuminated can drastically reduce suspicious activity.
• Hybrid Work Realities
  With staff arriving at unpredictable times, it’s easy for someone unfamiliar to blend in. Emphasise that it’s perfectly fine (and encouraged) to politely verify unfamiliar faces or ask to see a badge, even in a more relaxed corporate environment.

• Security Presence
  Large enterprises often have on-site security personnel or a contracted security company. Make sure employees know who these guards are and the basic protocols to follow—especially if someone arrives claiming to be “with security” but doesn’t seem legit.
• Drills & Communication
  Despite busy schedules, regular security awareness sessions and mock drills are invaluable. Employees need to know how to spot suspicious behaviour—like a “visiting IT technician” plugging unknown devices into a conference room jack—and feel comfortable reporting it. A culture of open communication about security concerns keeps everyone safer. Way too often I will walk around completely uninterrupted plugging who knows what into any port I can find without being stopped.

• Secure Entrances & Doors
  Many enterprises have multiple entrances—some for visitors, others for deliveries or staff only. Make sure these points are clearly marked, properly secured, and monitored. Card-access doors and reception check-ins serve as effective controls without feeling overly restrictive.
• Privacy Filters
  One of the easiest ways to prevent “shoulder surfing” is by using privacy filters on displays—especially in open-plan offices or shared meeting spaces where curious eyes might wander. It’s a low-cost, high-impact measure that every large company should consider adopting.

Best Practices (With a Nod to Recognized Frameworks)

1. Risk Assessment
   Conduct regular evaluations. Frameworks like NIST SP 800-53 or ISO 27001 provide strong guidance for identifying physical and digital threats.
2. Layered (Defense-in-Depth) Security
   Locking doors, monitoring CCTV, and training staff to spot unusual behavior create multiple layers an intruder must overcome.
3. Maintenance & Upgrades
   If your security hardware or software is outdated, it’s only a matter of time before someone exploits it. Keep everything patched and up to date.
4. Integration with Cybersecurity
   Blend physical and digital intelligence. For instance, alert the IT team if someone enters a restricted server room after hours.
5. Employee Engagement
   This is where the shared responsibility piece truly lives. Employees must know it’s okay to challenge or report anomalies. Collective vigilance is a must.

Physical security isn’t just about locks and cameras; it’s about creating a culture where every single person in the organisation understands their part in keeping the place safe. The organisation may hold 100% of the liability, but each employee needs to shoulder a slice of accountability every time they walk through the door. Because at the end of the day, even the strongest firewall won’t save you if someone forgets to lock the front door.

So, what about you? Which physical security measure—basic or high-tech—has made the biggest difference for your organisation? Always interesting to hear how people overcome physical security hurdles. Not all buildings can be locked down effectively, I’m sure others have found the same issue!