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Chapter 8. Hardware and Network Protection

segment where inbound traffic from the Internet would only be able to access those services in the

DMZ. This is effective in that, even though a malicious user exploits a machine on the DMZ, the rest

of the Internal network lies behind a firewall on a separated segment.

Most enterprises have a limited pool of publicly routable IP addresses from which they can host

external services, so administrators utilize elaborate firewall rules to accept, forward, reject, and deny

packet transmissions. Firewall policies implemented with

iptables

or dedicated hardware firewalls

allow for complex routing and forwarding rules, which administrators can use to segment inbound

traffic to specific services at specified addresses and ports, as well as allow only the LAN to access

internal services, which can prevent IP spoofing exploits. For more information about implementing

iptables

, refer to Chapter 7.

8.2. Hardware Security

According to a study released in 2000 by the FBI and the Computer Security Institute (CSI), over

seventy percent of all attacks on sensitive data and resources reported by organizations occurred from

within the organization itself. Implementing an internal security policy appears to be just as important

as an external strategy. The following sections explain some of the common steps administrators and

users can take to safeguard their systems from internal malpractice.

Employee workstations, for the most part, are not as likely to be targets for remote attack, especially

those behind a properly configured firewall. However, there are some safeguards that can be imple 

mented to avert an internal or physical attack on individual workstation resources.

Modern workstation and home PCs have BIOSes that control system resources on the hardware level.

Workstation users can also set administrative passwords within the BIOS to prevent malicious users

from accessing the system. BIOS passwords prevent malicious users from booting the system at all,

deterring the user from quickly accessing or stealing information stored on the hard drive.

However, if the malicious user steals the PC (the most common case of theft frequent travelers who

carry laptops and other mobile devices) and takes it to a location where they can disassemble the PC,

the BIOS password does not prevent the attacker from removing the hard drive, installing it in another

PC without BIOS restriction, and mount the hard drive to read any contents within. In these cases, it

is recommended that workstations have locks to restrict access to internal hardware. Hardware such

as lockable steel cables can be attached to PC and laptop chassis to prevent theft, as well as key locks

on the chassis itself to prevent internal access. Such hardware is widely available from manufacturers

such as Kensington and Targus.

Server hardware, especially production servers, are typically mounted on racks in server rooms. Server

cabinets usually have lockable doors; and individual server chassis also are available with lockable

front bezels for increased security from errant (or intentional) shutdown.

Enterprises can also use co location providers to house their servers, as co location providers offer

higher bandwidth, 24x7 technical support, and expertise in system and server security. This can be an

effective means of outsourcing security and connectivity needs for HTTP transactions or streaming

media services. However, co location can be cost prohibitive, especially for small to medium sized

businesses. Co location facilities are known for being heavily guarded by trained security staff and

tightly monitored at all times.