Analogies
Internet security is often described in military terms. Many of these originate from the castle building vocabulary of England during the reign of Edward II. I've always found this analogy interesting. Recently, I received an email from someone who read an article I wrote in the TISC newsletter, entitled Server vs. Client-based Protection. In that article, I made a brief reference to Edwardian period castles. A year later, I wrote a section for a chapter of a book my partner Lisa and I never completed. I found that chapter and decided I'd revise and publish it section by section. Today, I'll compare the Edwardian period "security" to Internet Security.
Castles protected items of value and people of importance - the landowners and merchants - from miscreants, robbers, and armies of rival lords who would steal or destroy valuables, and injure the nobility, if not prevented from doing so. Castle designers employed layers of security to protect the donjon or keep, its occupants and treasure. Rudely constructed dirt fortifications improved over time to what we all imagine when we think of a "castle": a formidable fortress surrounded by moats, accessible only via a draw bridge, with yeomen and archers positioned on crenellated and battlemented walls of stone to keep intruders at bay.
Within these layers of defense, men at arms stationed at checkpoints allowed recognized inhabitants and authorized visitors to come and go as they pleased within the confines of the castle walls, but only permitted a privileged few to access the keep itself. Barred gates, tripwires and mantraps were used to block and delay intruders who managed to make their way past any given line of defense. Alarm fires and bells were used to raise a general call to arms when defenses were breached.
We deploy similar physical security measures today to protect computing facilities (Internet data and operations centers). We try to maintain a secure perimeter, a continuous fortification or enciente continue surrounding our networks and the electronic assets within. Physical security measures to protect networks and communications systems still include walls and armed guards at checkpoints. Electronic sensors, laser tripwires and even mantraps are common components of physical security where the value of electronic assets and the systems on which they are stored or operated is particularly high (e.g., financial institutions). Electronic swipe cards and biometric devices (fingerprint, iris, and palm scans, and facial recognition) replace and complement armed guards as preferred methods of verifying identities of those who have authorized access to secure facilities.
Physical security doesn't cover the problems associated with protecting electronic valuables and trusted communities of individuals (insiders) from miscreants, competitors, terrorists and rogue governments (outsiders), who could access these assets via an organization's Internet connection(s) unless measures were taken to prevent them from doing so. Additional security measures are often required:
Perimeter security enforcement systems - packet-filtering routers, firewalls, and application proxies - prevent unauthorized access and block attacks.
Authentication systems distinguish authorized users (members of the trusted community) from unauthorized ones.
Network admission and endpoint control prevent devices that are judged "unsafe" from connecting to networks.
Authorization services - on client and server operating systems and file systems provide additional access controls and govern the activities authorized users may perform.
Intrusion prevention, detection and blocking systems - Intrusion Detection Systems (IDS), tripwires, honeypots, anti-virus and server integrity software and hardware - provide additional lines of defense within the secured perimeter, and provide alarms warning administrators of security breaches.
A castle proved very effective so long as the treasures weren't moved and the population of the kingdom didn't venture beyond the stationary defenses their castles provided. But for nobles and their merchants, travel was inevitable and communication with other kingdoms necessary. Armed guards accompanied the noble's entourages and the merchant's trade wagons. Knights accompanied the wagons for added protection. Treasures were transported in strongboxes. Private correspondence was sealed and uniquely imprinted with wax and chop (or signet ring).
Networks and hence network security were also based on isolationist practices as well. But wholly isolated, private networks are as impractical today as isolated kingdoms were during Edward's reign. Most organizations must have Internet presence, and its employees must access Internet resources, from the office, at home, and while they travel. Thus, every organization today has information assets that must be protected from misuse, abuse, theft or damage from outsiders. Many organizations have mobile workforces and teleworkers. Increasingly, organizations allow business partners, customers and consumers to access information via intranets and extranets. Organizations exchange sensitive correspondence and perform business transactions electronically, over the Internet, as well. These organizations are growing more aware of the threats Internet-originated attacks pose, and want to protect access to their information assets, and to protect information exchange over the Internet of as well; so additional security measures are often required.
One of the most widely employed measures is Virtual Private Networkings (VPN). A VPN uses encryption methods to protect information exchanged over the Internet - or generally, any communications path that is not considered "trusted" (especially wireless networks) - from being read, modified, and replayed. VPNs also authenticate both ends (parties) of a communication. But VPNs are one of several measures required to maintain distributed security policy enforcement. Once a client and mobile computing platform ventures be-yond the security measures commonly provided by an organization at one of its facilities, it must be protected with commensurate security measures. Desktop anti-virus, personal fire-wall, system integrity, and IDS software extend an organization's security enforcement be-yond the physical and logical perimeter it creates at one of its facilities. Distributed security policy enforcement, layered security, and defense in depth will appear as recurring themes in WLAN security.
The analogy between Edwardian period and network security is interesting, accurate, and powerful.
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by Dave Piscitello