Unix/Linux Security

Course Overview

The UNIX family of operating systems, including the Linux versions, is prized by IT professionals for its flexibility and openness. However, vulnerabilities can make UNIX systems susceptible to information assurance threats.

In this course, you gain the skills needed to secure your UNIX and Linux platforms. You learn to use tools and utilities to assess vulnerabilities, detect configurations that threaten information assurance and provide effective access controls.

Audience

This course is valuable for UNIX systems administrators and others responsible for deploying secure open systems. Course 428, " UNIX Introduction ", or Course 143, " Linux Introduction ", or equivalent experience is assumed.

Skills Gained

You will learn to:

• Secure UNIX and Linux systems from internal and external threats
• Control authenticated access to local and remote resources
• Scan servers for vulnerabilities and correct the problems that are found
• Reduce security risk by limiting superuser privileges
• Configure tools and utilities to minimise exposure and detect intrusions
• Tackle security problems by swapping out insecure software components

Course Outline

UNIX and Security

Achieving UNIX security

• Detecting intrusions with audits and logs
• Avoiding security loopholes
• Discovering software vulnerabilities and configuration errors

Protecting data and systems with cryptography

• Pretty Good Privacy (PGP)
• Gnu Privacy Guard (GnuPG)
• Authenticity and integrity through digital signatures and cryptographic hashes

Protecting User Accounts and Strengthening Authentication

Controlling secure account usage

• The UNIX login process
• Enforcing password quality and account use policy
• Controlling access with Pluggable Authentication Modules (PAM)
• Logging all account access and login failures

Monitoring and disabling accounts

• Tracking account usage
• How and when to disable accounts
• Managing user and group IDs

Logging in across the network

• Risks of trusted hosts and networks
• Providing strong authentication for login with S/Key, tokens and OPIE
• Tunneling application protocols through SSH

Reducing Exposure to Threats by Limiting Superuser Privileges

Controlling root access

• Configuring secure terminals
• Preventing insecure network access
• Gaining root privileges with su
• Using groups instead of rootidentity

Auditing superuser activity

• Limiting access to privileged accounts
• Detecting misuse and attacks with log files

Role-based access control (RBAC)

• Risks of UNIX all-or-nothing access
• RBAC in Solaris
• Adding RBAC with sudo

Safeguarding Vital Data by Securing Local and Network File Systems

Directory structure and partitioning for security

• Files, directories, devices and links
• Employing read-only partitions
• Ownership and access permissions
• Immutable and append-only files
• Identifying NFS vulnerabilities

Backup and integrity testing

• Safeguarding backed-up data
• Detecting intrusions with Tripwire

Hardening UNIX systems

• Increasing information assurance with yassp, TITANand Bastille
• Defending against DOS attacks
• Detecting weak configuration choices with Sussen

Avoiding the Exploitation of Programs

Risks from unwanted program execution

• Starting programs surreptitiously
• Running programs as other users
• Scheduling jobs with cronand at
• Minimising start-up script vulnerabilities

Reacting to attacks and intrusions

• Finding signs of intrusion in syslog data
• Analysing a compromised system
• Reducing the effects of buffer overflow exploits

Minimising Threats to Network Services

TCP/IP and its security loopholes

• Sniffing passwords with Ethereal and dsniff
• Testing network exposure with netstat , Isof and nmap

Securing internal network services

• Enabling enhanced logging
• Configuring OpenSSH and OpenSSL
• Network authentication using Kerberos
• X Window System vulnerabilities/solutions

Safely connecting to external networks

• Controlling and logging server access with TCP wrappers and xinetd
• Reducing information leakage
• Securing FTP, e-mail and Web access

Follow On Courses

• System and Network Security Introduction
• Securing Wireless Networks
• Disaster Recovery Planning
• Critical Thinking and Problem Solving
• SQL Server 2005 Reporting Services
• Linux Administration and Support

Unix/Linux Security / 433