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Physical Security Measures


220-1002: Objective 2.1: Summarize the importance of physical security measures.

Physical security of IT equipment is a fundamental first factor in a secure network. As mentioned earlier, data is typically the most valuable asset in a company, and leaving it in an unlocked area is dangerous in two ways. First, computer equipment is valuable, and a thief may want it for its face value, not caring about the valuable data it may contain or harm its release may do to customers. Second, an unlocked door is an invitation for someone to install sniffing equipment and gain access to company network assets well beyond the physical room left unattended. In the realm of physical security, there are several measures an IT professional must understand and practice.


Some secure areas include what is known as a mantrap, which is an area with two locking doors. A person might get past a first door by way of tailgating but might have difficulty getting past the second door, especially if there is a guard in between the two doors. A mantrap essentially slows down the entry process in hopes that people sneaking in behind others will be thwarted before gaining entry to the secure area. If the person doesn’t have proper authentication, he will be stranded in the mantrap until authorities arrive.

Badge Reader

Badge readers are devices that can interpret the data on a certain type of ID. While photo IDs are still best assessed by humans, other types of IDs add extra security that can be read by badge readers.

ID badges and readers can use a variety of physical security methods, including the following:

  • Photos: If the bearer of the card doesn’t look like the person on the card, the bearer might be using someone else’s card and should be detained.

  • Barcodes and magnetic strips: The codes embedded on these cards enable the cards to carry a range of information about the bearers and can limit individuals’ access to only authorized areas of buildings. These cards can be read quickly by a barcode scanner or swipe device.

  • RFID technology: Like barcoded badges, cards with radio-frequency identification (RFID) chips can be used to open only doors that are matched to the RFID chip. They can also track movement within a building and provide other access data required by a security officer.

To prevent undetected tampering, ID badges should be coated with a tamperevident outer layer.

Smart Card

A smart card is a credit card–sized card that contains stored information and might also contain a simple microprocessor or an RFID chip. Smart cards can be used to store identification information for use in security applications and to store values for use in prepaid telephone or debit card services, hotel guest room access, and many other functions. Smart cards are available in contact and contactless form factors.

Contactless cards are also known as proximity cards. Readers for these cards are usually wall mounted so users can scan their cards within 6 inches of a reader.

A smart card–based security system includes smart cards, card readers that are designed to work with smart cards, and a back-end system that contains a database that stores a list of approved smart cards for each secured location. Smart card–based security systems can also be used to secure individual personal computers.

To further enhance security, smart card security systems can also be multifactor, requiring the user to input a PIN or security password as well as provide the smart card at secured checkpoints, such as the entrance to a computer room.

Security Guard

Even the best security plans can be foiled by a determined and skillful thief. The best way to deter a thief is to use a mix of technical barriers and human interaction. Guards can be deployed in different ways. When employees enter the work area in the presence of a guard, it is more likely that best practices will be followed and everyone will scan in and be authenticated. Without a guard, it is more common for people to hold the door for people who are recognized but say they have misplaced their IDs. Knowing that someone is watching carefully keeps honest people honest and those who are dishonest away from the door.

Another way to deploy guards is to have them watch several areas via security cameras that record access into and out of the buildings. While this method is not as effective as posting a guard at each door, it makes it possible for fewer security guards to scan different areas for traffic behaviors that warrant further attention.

Door Lock

Of course, the easiest way to secure an area is to lock doors. While this seems an obvious statement, it is surprisingly common for people to get to unauthorized areas by just wandering in. Some organizations have written policies explaining how, when, and where to lock doors. Aside from main entrances, you should also always lock server rooms, wiring closets, labs, and other technical rooms when not in use.

Physical door locks might seem low tech, but they can’t be taken over by hackers. Other precautions to take include documenting who has keys to server rooms and wiring closets and periodically changing locks and keys. Cipher locks that use punch codes also enhance security. Using a combination of these methods provides for greater protection.

Biometric Locks

Biometric security refers to the use of a person’s biological information—through fingerprint scanning, retina scanning, or facial recognition, for example—to authenticate potential users of a secure area. The most common type of biometric security system for PCs is fingerprint based, but other methods include voice measurements, facial recognition, and scans of the eye’s retina or iris. Newer versions of device security that use fingerprint and facial recognition are Microsoft’s Hello (available in Windows 10) and Apple Face ID on newer iPhones.


Any physical device that a user must carry to gain access to a specific system can be called a token. Examples are smart cards, RFID cards, USB tokens, and key fobs. (Key fob hardware tokens are explained later in this section.)

Laptop and Cable Locks

Most desktops, laptops, and many other mobile devices such as projectors and docking stations feature a security slot. On a laptop, the slot is typically located near a rear corner (see Figure 7-1).


FIGURE 7-1 A Security Slot on a Laptop

This slot is used with a laptop cable lock, such as the one shown in Figure 7-2. Laptop locks use a combination or keyed lock and are designed to lock a laptop (or other secured device) to a fixed location such as a table.


FIGURE 7-2 A Combination Laptop Security Lock

Server Locks

Even with building security in place, it may be necessary to have more granular security in place in areas like server rooms. A data center might contain equipment from several different companies, and non-employees may need access to server areas. Of course, not all threats are external, and some employees who have access to equipment areas should also have access to server equipment in the data center.

Rack-level security involves locking down equipment in a server rack. This can be done with cabinets or cages with secure biometric locks or perhaps keycards that can be changed often. Security cameras are appropriate in data centers as well. Rack cabinets can be quite sophisticated, with alarms that indicate access and improperly closed doors.

Examples of rack level security can be seen at https://tzsmartcabinets.net.

USB Locks

It is possible for someone to remove a USB cable from a computer and insert another USB device (or simply plug into an empty USB port), making it possible for a thief to then move data from the computer. USB locks can be used to secure USB cables into the computer and to securely plug empty USB ports. One manufacturer of these specialty port locks is PadJack (http://www.padjack.com/usb-cable-lock-seal/).

Privacy Screen

Privacy issues are important to any company that handles confidential data, and when such data is being used on a workstation screen or mobile device, it needs to be protected from unintentional viewing. Data on a computer screen can be easily protected by installing a privacy screen, which is a transparent cover for a PC monitor or laptop display. It reduces the cone of vision, usually to about 30 degrees, so that only the person directly in front of the screen can see the content. Many of these screens are also antiglare, helping to reduce the user’s eye strain.

Key Fobs

Key fobs can be used with a variety of security devices. They can contain RFID chips, and many key fobs are used as part of a two-step authentication protocol that works as follows:

  • The user carries a key fob that generates a code every 30 to 60 seconds. Every time the code changes on the fob, it is also matched in the authentication server. In some cases, the user must also log into the fob to see the access code for an extra layer of security.

  • The user then logs into the system or restricted area, using the randomly generated access code displayed on the key fob’s LCD display. The authentication server matches the current code and allows access.

A key fob used in this way is often referred to as a hardware token.

Entry Control Roster

An entry control roster, which is a list of individuals or representatives who are authorized to enter a secured area, can be used with a variety of security systems. Potential entrants can be looked up on an entry control roster and granted access if their credentials match those listed. A keypad lock on an entrance to a secure area can store a list of authorized PINs. Only users with recognized PINs can enter the secure area. Logs are usually kept to record who entered and exited a room at different times.

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