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ContentsContents
Security and Hardening Guide
  1. Preface
  2. 1 Security and confidentiality
  3. I Authentication
    1. 2 Authentication with PAM
    2. 3 Using NIS
    3. 4 Setting up authentication clients using YaST
    4. 5 LDAP with 389 Directory Server
    5. 6 Network authentication with Kerberos
    6. 7 Active Directory support
    7. 8 Setting up a freeRADIUS server
  4. II Local security
    1. 9 Physical security
    2. 10 Software management
    3. 11 File management
    4. 12 Encrypting partitions and files
    5. 13 Storage encryption for hosted applications with cryptctl
    6. 14 User management
    7. 15 Restricting cron and at
    8. 16 Spectre/Meltdown checker
    9. 17 Configuring security settings with YaST
    10. 18 The Polkit authentication framework
    11. 19 Access control lists in Linux
    12. 20 Intrusion detection with AIDE
  5. III Network security
    1. 21 X Window System and X authentication
    2. 22 Securing network operations with OpenSSH
    3. 23 Masquerading and firewalls
    4. 24 Configuring a VPN server
    5. 25 Managing a PKI with XCA, X certificate and key manager
    6. 26 Improving network security with sysctl variables
  6. IV Confining privileges with AppArmor
    1. 27 Introducing AppArmor
    2. 28 Getting started
    3. 29 Immunizing programs
    4. 30 Profile components and syntax
    5. 31 AppArmor profile repositories
    6. 32 Building and managing profiles with YaST
    7. 33 Building profiles from the command line
    8. 34 Profiling your Web applications using ChangeHat
    9. 35 Confining users with pam_apparmor
    10. 36 Managing profiled applications
    11. 37 Support
    12. 38 AppArmor glossary
  7. V SELinux
    1. 39 Configuring SELinux
  8. VI The Linux Audit Framework
    1. 40 Understanding Linux audit
    2. 41 Setting up the Linux audit framework
    3. 42 Introducing an audit rule set
    4. 43 Useful resources
  9. A GNU licenses
Navigation
Applies to openSUSE Leap 15.6

Part III Network security Edit source

21 X Window System and X authentication

Network transparency is one of the central characteristics of a Unix system. X, the windowing system of Unix operating systems, can use this feature in an impressive way. With X, it is no problem to log in to a remote host and start a graphical program that is then sent over the network to be displa…

22 Securing network operations with OpenSSH

OpenSSH is the SSH (secure shell) implementation that ships with openSUSE Leap, for securing network operations such as remote administration, file transfers, and tunneling insecure protocols. SSH encrypts all traffic between two hosts, including authentication, to protect against eavesdropping and connection hijacking. This chapter covers basic operations, plus host key rotation and certificate authentication, which are useful for managing larger SSH deployments.

23 Masquerading and firewalls

Whenever Linux is used in a network environment, you can use the kernel functions that allow the manipulation of network packets to maintain a separation between internal and external network areas. The Linux netfilter framework provides the means to establish an effective firewall that keeps differ…

24 Configuring a VPN server

Internet connections are easily available and affordable. However, not all connections are secure. Using a Virtual Private Network (VPN), you can create a secure network within an insecure network such as the Internet or Wi-Fi. It can be implemented in different ways and serves several purposes. In this chapter, we focus on the OpenVPN implementation to link branch offices via secure wide area networks (WANs).

25 Managing a PKI with XCA, X certificate and key manager

Managing your own public key infrastructure (PKI) is traditionally done with the openssl utility. For admins who prefer a graphical tool, openSUSE Leap 15.6 includes XCA, the X Certificate and Key management tool (https://hohnstaedt.de/xca).

XCA creates and manages X.509 certificates, certificate requests, RSA, DSA and EC private keys, Smartcards and certificate revocation lists (CRLs). XCA supports everything you need to create and manage your own certificate authority (CA). XCA includes customizable templates that can be used for certificate or request generation. This chapter describes a basic setup.

26 Improving network security with sysctl variables

Sysctl (system control) variables control certain kernel parameters that influence the behavior of different parts of the operating system, for example the Linux network stack. These parameters can be looked up in the proc file system, in /proc/sys. Many kernel parameters can be changed directly by …

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