Chapter 13: Advanced Security and Beyond

1
Chapter 13 Advanced Security and Beyond

• Security Guide to Network Security Fundamentals
• Second Edition

2
Objectives

• Define computer forensics
• Respond to a computer forensics incident
• Harden security through new solutions
• List information security jobs and skills

3
Understanding Computer Forensics

• Computer forensics can attempt to retrieve
  informationeven if it has been altered or
  erasedthat can be used in the pursuit of the
  criminal
• The interest in computer forensics is heightened
• High amount of digital evidence
• Increased scrutiny by legal profession
• Higher level of computer skills by criminals

4
Forensics Opportunities and Challenges

• Computer forensics creates opportunities to
  uncover evidence impossible to find using a
  manual process
• One reason that computer forensics specialists
  have this opportunity is due to the persistence
  of evidence
• Electronic documents are more difficult to
  dispose of than paper documents

5
Forensics Opportunities and Challenges (continued)

• Ways computer forensics is different from
  standard investigations
• Volume of electronic evidence
• Distribution of evidence
• Dynamic content
• False leads
• Encrypted evidence
• Hidden evidence

6
Responding to a Computer Forensics Incident

• Generally involves four basic steps similar to
  those of standard forensics
• Secure the crime scene
• Collect the evidence
• Establish a chain of custody
• Examine and preserve the evidence

7
Securing the Crime Scene

• Physical surroundings of the computer should be
  clearly documented
• Photographs of the area should be taken before
  anything is touched
• Cables connected to the computer should be
  labeled to document the computers hardware
  components and how they are connected
• Team takes custody of the entire computer along
  with the keyboard and any peripherals

8
Preserving the Data

• Computer forensics team first captures any
  volatile data that would be lost when computer is
  turned off and moves data to a secure location
• Includes any data not recorded in a file on the
  hard drive or an image backup
• Contents of RAM
• Current network connections
• Logon sessions
• Network configurations
• Open files

9
Preserving the Data (continued)

• After retrieving volatile data, the team focuses
  on the hard drive
• Mirror image backup (or bit-stream backup) is an
  evidence-grade backup because its accuracy meets
  evidence standards
• Mirror image backups are considered a primary key
  to uncovering evidence they create exact
  replicas of the computer contents at the crime
  scene
• Mirror image backups must meet the criteria shown
  on pages 452 and 453 of the text

10
Establishing the Chain of Custody

• As soon as the team begins its work, must start
  and maintain a strict chain of custody
• Chain of custody documents that evidence was
  under strict control at all times and no
  unauthorized person was given the opportunity to
  corrupt the evidence

11
Examining Data for Evidence

• After a computer forensics expert creates a
  mirror image of system, original system should be
  secured and the mirror image examined to reveal
  evidence
• All exposed data should be examined for clues
• Hidden clues can be mined and exposed as well
• Microsoft Windows operating systems use Windows
  page file as a scratch pad to write data when
  sufficient RAM is not available

12
Examining Data for Evidence (continued)

• Slack is another source of hidden data
• Windows computers use two types of slack
• RAM slack pertains only to the last sector of a
  file
• If additional sectors are needed to round out the
  block size for the last cluster assigned to the
  file, a different type of slack is created
• File slack (sometimes called drive slack) padded
  data that Windows uses comes from data stored on
  the hard drive

13
Examining Data for Evidence (continued)
14
Examining Data for Evidence (continued)
15
Examining Data for Evidence (continued)
16
Hardening Security Through New Solutions

• Number of attacks reported, sophistication of
  attacks, and speed at which they spread continues
  to grow
• Recent attacks include characteristics listed on
  pages 457 and 458 of the text
• Defenders are responding to the increase in the
  level and number of attacks
• New techniques and security devices are helping
  to defend networks and systems
• The most recent developments and announcements
  are listed on pages 458 and 459 of the text

17
Exploring Information Security Jobs and Skills

• Need for information security workers will
  continue to grow for the foreseeable future
• Information security personnel are in short
  supply those in the field are being rewarded
  well
• Security budgets have been spared the drastic
  cost-cutting that has plagued IT since 2001
• Companies recognize the high costs associated
  with weak security and have decided that
  prevention outweighs cleanup

18
Exploring Information Security Jobs and Skills
(continued)

• Most industry experts agree security
  certifications continue to be important
• Preparing for the Security certification will
  help you solidify your knowledge and skills in
  cryptography, firewalls, and other important
  security defenses

19
TCP/IP Protocol Suite

• One of the most important skills is a strong
  knowledge of the foundation upon which network
  communications rests, namely Transmission Control
  Protocol/Internet Protocol (TCP/IP)
• Understanding TCP/IP concepts helps effectively
  troubleshoot computer network problems and
  diagnose possible anomalous behavior on a network

20
Packets

• No matter how clever the attacker is, they still
  must send their attack to your computer with a
  packet
• To recognize the abnormal, you must first
  understand what is normal

21
Firewalls

• Firewalls are essential tools on all networks and
  often provide a first layer of defense
• Network security personnel should have a strong
  background of how firewalls work, how to create
  access control lists (ACLs) to mirror the
  organizations security policy, and how to tweak
  ACLs to balance security with employee access

22
Routers

• Routers form the heart of a TCP/IP network
• Configuring routers for both packet transfer and
  packet filtering can become very involved

23
Intrusion-Detection Systems (IDS)

• Security professionals should know how to
  administer and maintain an IDS
• Capabilities of these systems has increased
  dramatically since first introduced, making them
  mandatory for todays networks
• One problem is that IDS can produce an enormous
  amount of data that requires checking

24
Other Skills

• A programming background is another helpful tool
  for security workers
• Security workers should also be familiar with
  penetration testing
• Once known as ethical hacking, probes
  vulnerabilities in systems, networks, and
  applications

25
Computer Forensic Skills

• Computer forensic specialists require an
  additional level of training and skills
• Basic forensic examinations
• Advanced forensic examinations
• Incident responder skills
• Managing computer investigations

26
Summary

• Forensic science is application of science to
  questions of interest to the legal profession
• Several unique opportunities give computer
  forensics the ability to uncover evidence that
  would be extremely difficult to find using a
  manual process
• Computer forensics also has a unique set of
  challenges that are not found in standard
  evidence gathering, including volume of
  electronic evidence, how it is scattered in
  numerous locations, and its dynamic content

27
Summary (continued)

• Searching for digital evidence includes looking
  at obvious files and e-mail messages
• Need for information security workers will
  continue to grow, especially in computer
  forensics
• Skills needed in these areas include knowledge of
  TCP/IP, packets, firewalls, routers, IDS, and
  penetration testing