Security Baselines - Network Security - Lecture Slides, Slides of Cryptography and System Security

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Chapter 4: Security Baselines

Objectives

• Disable nonessential systems
• Harden operating systems
• Harden applications
• Harden networks

Disabling Nonessential

Systems (continued)

• Early terminate-and-stay-resident (TSR) programs performed functions such as displaying an instant calculator, small notepad, or address book
• In Microsoft Windows, a background program, such as Svchostexe, is called a process
• The process provides a service to the operating system indicated by the service name, such as AppMgmt

Disabling Nonessential

Systems (continued)

• Users can view the display name of a service, which gives a detailed description, such as Application Management
• A single process can provide multiple services

Disabling Nonessential

Systems (continued)

Disabling Nonessential

Systems (continued)

• A service can be set to one of the following modes: - Automatic - Manual - Disabled
• Besides preventing attackers from attaching malicious code to services, disabling nonessential services blocks entries into the system

Disabling Nonessential

Systems (continued)

Hardening Operating Systems

• Hardening: process of reducing vulnerabilities
• A hardened system is configured and updated to protect against attacks
• Three broad categories of items should be hardened: - Operating systems - Applications that the operating system runs - Networks

Applying Updates

• Operating systems are intended to be dynamic
• As users’ needs change, new hardware is introduced, and more sophisticated attacks are unleashed, operating systems must be updated on a regular basis
• However, vendors release a new version of an operating system every two to four years
• Vendors use certain terms to refer to the different types of updates (listed in Table 4- on page 109)

Applying Updates (continued)

• A service pack (a cumulative set of updates including fixes for problems that have not been made available through updates) provides the broadest and most complete update
• A hotfix does not typically address security issues; instead, it corrects a specific software problem

Applying Updates (continued)

• A patch or a software update fixes a security flaw or other problem - May be released on a regular or irregular basis, depending on the vendor or support team - A good patch management system includes the features listed on pages 111 and 112 of the text

Securing the File System

• Another means of hardening an operating system is to restrict user access
• Generally, users can be assigned permissions to access folders (also called directories in DOS and UNIX/Linux) and the files contained within them

Securing the File System (continued)

• Group Policy settings: components of a user’s desktop environment that a network system administrator needs to manage
• Group Policy settings cannot override a global setting for all computers (domain-based setting)
• Windows stores settings for the computer’s hardware and software in a database (the registry)

Hardening Applications

• Just as you must harden operating systems, you must also harden the applications that run on those systems
• Hotfixes, service packs, and patches are generally available for most applications; although, not usually with the same frequency as for an operating system