What this book covers

Chapter 1, Linux Security Problems, covers various vulnerabilities and exploits in relation to Linux. It also discusses the kinds of security that can be implemented for these exploits. Topics include preparing security policies and security controls for password protection and server security and performing vulnerability assessments of the Linux system. It also covers the configuration of sudo access.

Chapter 2, Configuring a Secure and Optimized Kernel, focuses on the process of configuring and building the Linux kernel and its testing. Topics covered include requirements for building a kernel, configuring a kernel, kernel installation, customization, and kernel debugging. The chapter also discusses configuring a console using Netconsole.

Chapter 3, Local Filesystem Security, looks at Linux file structures and permissions. It covers topics such as viewing file and directory details, handling files and file permissions using chmod, and the implementation of an access control list. The chapter also gives readers an introduction to the configuration of LDAP.

Chapter 4, Local Authentication in Linux, explores user authentication on a local system while maintaining security. Topics covered in this chapter include user authentication logging, limiting user login capabilities, monitoring user activity, authentication control definition, and also how to use PAM.

Chapter 5, Remote Authentication, talks about authenticating users remotely on a Linux system. The topics included in this chapter are remote server access using SSH, disabling and enabling root login, restricting remote access when using SSH, copying files remotely over SSH, and setting up Kerberos.

Chapter 6, Network Security, provides information about network attacks and security. It covers managing the TCP/IP network, configuring a firewall using Iptables, blocking spoofed addresses, and unwanted incoming traffic. The chapter also gives readers an introduction to configuring and using TCP Wrapper.

Chapter 7, Security Tools, targets various security tools or software that can be used for security on a Linux system. Tools covered in this chapter include sXID, PortSentry, Squid proxy, OpenSSL server, Tripwire, and Shorewall.

Chapter 8, Linux Security Distros, introduces the readers to some of the famous distributions of Linux/Unix that have been developed in relation to security and penetration testing. The distros covered in this chapter include Kali Linux, pfSense, DEFT, NST, and Helix.

Chapter 9, Patching a Bash Vulnerability, explores the most famous vulnerability of Bash shell, which is known as Shellshock. It gives readers an understanding of Shellshock vulnerability and the security issues that can arise with its presence. The chapter also tells the reader how to use the Linux Patch Management system to secure their machine and also gives them an understanding of how patches are applied in a Linux system.

Chapter 10, Security Monitoring and Logging, provides information on monitoring logs in Linux, on a local system as well as a network. Topics discussed in this chapter include monitoring logs using Logcheck, using Nmap for network monitoring, system monitoring using Glances, and using MultiTail to monitor logs. A few other tools are also discussed, which include Whowatch, stat, lsof, strace, and Lynis.