ccna certification book 2020

ccna certification book 2020.Industry-recommended practices -------------- What are the reliable, easy-to-understand, and recommended security practices currently deployed by other organizations similar to our organization? Security operations - What are the current protocols used for incident response, monitoring, maintenance, and auditing system compatibility?10.1.1.2 Avoiding False AssumptionsMany security assumptions are made when designing and implementing a secure network. Unfortunately, assumptions about how and where the system will be used can lead to security mechanisms being broken, misconfigured, or bypassed. For example, a bad assumption is to assume that more users will need to use a protocol such as FTP than is actually the case.Other historical examples of bad security assumptions are the following.296 Chapter io Managing a Secure NetworkThe original DVDs were encrypted using a weak encryption algorithm called ContentScramblingSystem (CSS). This was because it was assumed that DVDs could only be played on a hardware player with a tamper-resistant decryption chip. However, the DVDs were soon reverse-engineered and their decryption keys were recovered and distributed with the movies on the Internet. Initially cellular traffic in the United States was not encrypted because it was assumed that the cost of using scanners to intercept cellular traffic was quite high. However, the price of these scanners has fallen dramatically, thus threatening the protection strategies of cellular networks as well.A false assumption can negatively impact all design efforts. It can affect a particular design decision and then ripple through other decisions that depend on it. The wrong decision is particularly dangerous in the early stages of security system design, when threats are modeled and when risk reviews are performed. For example, it is often relatively easy to correct or enhance a single implementation in a system, such as modifying the configuration of a firewall. However, design errors, such as where this firewall is placed, can be extremely difficult or even impossible to correct without a significant investment of time and technology.Here are some guidelines to help avoid making incorrect assumptions. Have an expectation that any aspect of a security system can fail. When designing a system, perform a what-if analysis of each element's failure, assess the probability of failure, analyze all possible consequences of a failure, and consider cascading failures of other elements.