ccna 6.0 exam

ccna 6.0 exam.6.1.1.3 Trust Codes and Trust PathsThe operating system provides basic security services for applications.Trust codes and trust paths - ensuring that the integrity of the operating system is not violated. Trusted code refers to ensuring that the operating system code is not compromised. The operating system can provide integrity checks on all running code through the use of hash message authentication codes (HMAC) or digital signatures. It may also be necessary to perform integrity checks when installing additional software. It is also possible to use digital signatures at the same time. A trusted path is a tool that ensures that the user is using a real system process and not a Trojan horse. An example of a trust path is the Ctrl-Alt-Delete keystroke sequence, which ensures that the user is not using a fake or simulated user login screen.Privilege enforcement environment - provides authentication and privileges determined based on identity.148 Chapter 6 Protecting the Local Area Network. Process storage protection and isolation-separating other users and their data. Access control to resources-ensuring the confidentiality and integrity of data.An attacker can compromise all of these services. If the trust code and trust path pairs are not ready or are compromised, then the operating system and all applications can be easily compromised by malicious code. If support for legacy protocols is required, then the operating system may be more vulnerable.6.1.1.4 Operating System VulnerabilitiesModern operating systems provide each process with an identity and privileges. Privilege switching can occur while a program is running or while in a single login session. For example, UNIX uses the suid (set user ID) tool, while Windows uses the ninas program. The ultimate goal of an attacker is often to run an application on the host and use it to obtain the sensitive data the attacker wants. An attacker's attack on a pair of applications can be direct or indirect.