Social engineering Cryptographic Assaults

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2.4.3 Network Compromises and Attacks

Why would somebody want to hurt your site? If you have any public visibility, you could well attract unwanted attention from unsavory characters who are holding a grudge, nosy competition trying to ferret out new product information, or disgruntled employees out for a joyride.

2.4.3.1 Denial of service attacks

These types of attacks are usually hate- or vendetta-driven, because they have only one aim: to prevent you or anyone else, for that matter from using your own equipment. A couple of strategies of this nature are: flooding a network interface with traffic, making use of the whole network impossible, or sending specific invalid packets to a computer that cause it to crash several times an hour. A good analogy for this type of attack would be someone wasting your whole afternoon by repeatedly calling you and hanging up. Although there is little you can do in this instance, once an attack is isolated, a system administrator can use a firewall to block inbound requests that would normally cripple the machine or the network. Unfortunately, there is only experimental work being done right now that would allow a scanning process or router to dynamically block such attacks when it notices them and verifies that they are valid threats.

2.4.3.2 Address spoofing

TCPIP, because of its widespread use, large-scale deployment, and ongoing worldwide development, is definitely the lingua franca of the Internet and will continue to be so. Enhancements to the lower levels of the protocol such as IPSec will not only support IPs use in a worldwide environment to deliver data, but will do so securely. The strengths derived from using the current IP implementation, unfortunately, make the protocol unsecure. Because of how packet routing works and how header information is constructed, it becomes very difficult to conclusively prove the path a packet takes from point A to point B, and difficult to guarantee that some packet originated from A to begin with. Because of this, attackers can masquerade or spoof their targets routers and systems into thinking packets originated from someplace they did not. By doing this, all manner of mischief can be wrought.

2.4.3.3 Session hijacking

By building a foundation of IP source spoofing in the above example, an attacker can effectively hijack an entire session between A and B. The parties need not be two individuals sending messages back and forth. More than likely, one of the parties involved will be a server of some sort, which the attacker will impersonate during the span of the communication. By posing as an organizations mail server or file server, he can collect a ton of private material and analyze it at his leisure.

2.4.3.4 Man-in-the-middle attack

Also built on the foundation of IP address spoofing, an attacker can not only stage a session hijack, but can also mimic A and complete the original requests made to B directly. Imagine that we are M, and are able to convince A we are B, and B we are A. Traffic sent to B from A could be caught by M, analyzed, modified, stored or merely witnessed, and then sent on to B, no one at all the wiser. Traffic returning from B to A could be treated in a similar fashion. The 40 VPNs discussed in the book rely upon sophisticated techniques for combating the man-in-the- middle attack, sometimes relying upon per-packet or time-oriented authentication, or even the quick shifting of keys.

2.4.3.5 Replay attack

A replay attack is essentially what would happen if an attacker were to record a transmission from A to B, even if the attacker is unable to read the message, then replay the message at a later time. Sometimes attacks of this nature can work if used in concert with an IP spoofing assault or even a man-in-the-middle one. Some VPNs combat this threat by serializing the packets, some by encapsulating the IP header as well as the datagram, and some by using synchronized timestamping. A combination of these techniques could also be used.

2.4.3.6 Detection and cleanup

Computer break-in incidents are difficult to detect and more difficult to prosecute. According to the Computer Emergency Response Team CERT, a full 35 of all high-degree break-ins go completely undetected by the system administrators responsible for the equipment compromised; an even higher 85 of all incidents go unreported. Sometimes it is only by accident that an administrator notices the tell-tale symptoms of a break-in. Strange things found in the temporary directory, strange processes running, applications found that were not distributed with the operating system, and users reporting that they are having trouble logging in or have forgotten their passwords somehow are clues. When attackers are careful to clean up after themselves, the odds that someone will notice decrease dramatically. If they are careless or just joyriders, detection is much easier and cleanup is simpler. The biggest gut-wrenching feeling occurs when the attacker seems not to have changed anything. If only a minimal clue to their penetration is left, you can be assured that you need to sanitize—and quickly. For a whole host of security-related documents, including current advisories, check with CERT directly at http:www.cert.org . In closing, always try to be quick to respond to any threat or apparent break-in as soon as you are notified or as soon as you discover it. The faster you are at taking care of things, the less impact there is overall. Even though you are sure to have a restricted budget and inadequate resources for your security efforts, try to follow through with all measures you can take to pursue the attackers. If they think you are too busy or uncaring, they will come back, with better tricks and harsher consequences. Be attentive to what they were trying to do as well as what they did. If you can connect the dots, you may put yourself in front of them, and possibly even catch them. Dont just assume they will disappear or that they didnt really do anything anyway. Just to reiterate: keep good backups, change user accounts and passwords regularly, and develop a registry for access and authentication levels that can be deployed organization-wide.

2.5 Patents and Legal Ramifications

Cryptographic routines are complex mathematical systems, and the people who have created them are experts who have spent a great deal of resources to create and protect their systems.