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Audit

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					Auditing: Measuring something against a standard
                       How do you know you…?
                        Objectives
The student shall be able to:
 Define audit, vulnerability, threat, policy, policy objective, policy
  control, procedure, baseline, auditor, audit exception, and audit
  exception root cause.
 Describe the purpose of a baseline, and the contents of a Network
  Traffic Baseline and System Baseline.
 Define the terms protection, detection, response, and exposure, given
  an example time-based security situation.
 Describe the purpose of the audit plan’s scope, purpose, checklist,
  policy resource guideline, audit strategy.
 Write an audit plan.
 Describe the purpose of each stage of an audit.
 Describe important points of staying out of jail while doing an audit.
 Conduct a complete audit, procedurally.
There is no reading this week. Work on your audit plan/report
                Types of Audits
Security Audit: Measures how well our security
  policies/procedures are relative to best-in-class
    Assessment or Verification: Analysis of security
     improvements. Are our procedures effective?
Conformance Audit: Measures how well a system or process
 conforms to policies/procedures
    Validation: How well are we following our guidelines?


Firewall example:
 Validation: Is it really protecting us?
 Assessment: Is our plan effective?
                  Vocabulary
 Vulnerability: An unlocked door in infrastructure or
  organization
 Vulnerability Assessment: An evaluation of
  potential vulnerabilities related to the described scope

 Threat: An action that exposes a vulnerability
   Examples: File deletion, information exposure, improper
    use of assets, malware attack
   Intentional versus Accidental Threat: Both have same
    effect
 Exposure = Vulnerability + Threat
        Security Documentation
Policy: Requirements Rule:           Example 1:
  Describes ‘what’ needs to be        Policy Objective: Reduce
  accomplished                         highway deaths
 “Only students currently            Policy Control: Set speed limit
  enrolled in computer science         to 55
  courses shall have access to the
  computer science lab”
                                     Example 2:
                                      Policy Objective: Differentiate
Policy Objective: Describes why        between different users on a
  the policy is required               system
Policy Control: Technique to          Policy Control: Logon
  meet objectives                      restrictions, smart card,
 May include a procedure              biometric authentication

                                       Discussion: Are these effective
                                       controls by themselves?
                    Procedure
Procedure: Outlines ‘how’ the Policy will be
  accomplished
1. “The CS System Administrator shall provide a list of
    student IDs to the lab entrance system by running
    the XXX program using the YYY file one week before
    classes begin.”
2. “Students must slide their student ID card through
    the card reader and enter the last four digits of their
    SSN to gain entry at the CS lab door”
                    Baseline
Baseline: Snapshot of a system in a Known Good State
 Is a static measure of a system
 Enables recognition of changes in system via activity
  profiles
 Enables description of how a system has changed
 Most useful when generated automatically
           Example Baselines
Example Baselines:
Network Traffic Baseline: Shows traffic volume per
  hour of day (Wireshark, Shadow/NFR IDS, etc.)
System Baseline: Shows OS version, available disk
  space, description of system files, size of different
  major directories…
 Start-> Run-> winver: Prints the version of OS
 Start-> Run-> winmsdo; File-> Export: Saves system
  baseline info
         Preparing a Baseline
Take a copy of a new system or

To achieve Known Good State:
 Update virus signatures
 Ensure system fully patched
 Do comprehensive virus scan
 Check all files (not just system files)
 Turn on heuristic virus scanning, which recognizes
  suspicious patterns in addition to signatures
 Save baselines to CD for offline storage
          Time Based Security
 Can we react to an attack quickly enough to control it?
 Defense in Depth requires multiple layers


 Exposure = Detection + Response
 Protection > Detection + Response
 Estimate Best and Worst Detection and Response
 Time to get Exposure
          Time-Based Examples
Example 1: Defending a Castle        Example 2: Home Alarm
 On a hill or mountain               An apt. alarm beeps for 15 seconds
                                       waiting for a passcode to be entered
 Has a moat                          The alarm takes 15 seconds to dial the
                                       security company
 Has an outer wall                   The security company takes 30
 Trees cut down around the wall       seconds to inform the police
                                      It takes the police 2-5 minutes to
Protection: How long will it take      arrive at the site
  to get through the multiple
  layers of defense?                 Protection:
                                      It takes one minute to empty a jewel
Detection: How long will it take        box in the bedroom and walk out
  for us to recognize an attack?      It takes n minutes to steal all
                                        expensive appliances in a home with
Response: How long will it take to      one person
  react to an attack?
                More Examples
                                  Example 5: Network Traffic
Example 3: USS Cole               Baseline
 USS Cole Attack Response:        Shadow IDS measures traffic
  Move all US military vessels      and reports hourly of traffic
  out of foreign ports and onto     against a baseline. What is best
  the open sea                      and worst Detection times?

                                  Example 6: Sluggish Web
Example 4: Edge router, IDS,        service
  Firewall
                                   What is best and worst
                                    Detection times?
                                   Implementation: Measure D + R
                                    using stopwatch
Results and Recommendations
Audit Exceptions: Items that fail to meet the audit
 criteria
Mitigation: Recommendation to reduce loss/harm
Remediation: How to fix an Audit Exception, by policy,
 procedure, best practice
Root Cause: Why is there an audit exception? Treat
 the illness, not the symptom
       Auditor Responsibilities
Responsibilities include:    Raising Awareness:
 Measure and report on       It’s not ‘if’ we’ll be
  risk                         hacked but ‘when’.
 Raise awareness of          You can never be too
  security issues in order     secure…
  to reduce risk
 Often provide input to
  policies and procedures
             Audit Plan Outline
Scope:
 What part of the organization are we auditing?
 Can audit a process, a technology, a department/division
 Example: “Enumerate vulnerabilities for a web server”

Objective:
 What do we hope to accomplish or measure through the audit?

Can include:
 Validation: Are rules implemented correctly?
 Baseline Comparison:
    Measure conformance to policy
    Measure if system has been compromised
       Audit Plan Outline Cont’d
Policy Resource Guidelines:
 Documentation for existing and recommended security guidelines

Audit Strategy:
 A definition of how the audit will occur. What tools and techniques will best
  meet the objectives?

Checklist:
 Each policy has a number of checklist line items
 Each checklist line item describes a procedure of what and how to measure a
  policy

Signatures:
 On cover page request signature of the audit team, the instructor, and the team
   from the audited company.
 Make sure that both you and company have signed copy of Audit Plan
       Policy Resource Guidelines
Company policies: Statement in full or summary

                                      Best Practice references:
Center for Internet Security: www.cisecurity.org
 Provides documents that can easily be used as part of an audit checklist, including procedures,
   standards, tools, benchmarks

COBIT: Control OBjectives for Information and related Technology: www.isaca.org/cobit.htm
 IT-oriented framework for control and mgmt of an organization


FISCAM: Federal Information Systems Control Audit Manual www.ignet.gov/pande/faec/fiscam.pdf
 Used by US GAO and many Inspector General Offices
 Focuses on Financial Applications of IT


ISO/IEC 27002:2005 Information technology -- Security techniques -- Code of practice for information
   security management.
 International Standard
        Audit Process Outline
Audit Process includes:
 Audit Planning: Create Audit Plan
 Entrance Conference: Inform people of process
 Fieldwork: Measurement of the system
 Report Preparation: Complete report
 Exit Conference: Discuss report with affected
  personnel
 Report to Management: Provide revised report to
  management
        Step 1: Audit Planning
 Auditor works with contracting individual to
  determine scope/purpose of audit
 Research corporate policies, industry best standards
 Prepare audit strategy, checklist, and audit procedures
   Step 2: Entrance Conference
 Auditor meets with all people involved in the audit
 Mgmt schedules the meeting, including mgmt, security, system
  administrators, users being audited (e.g., if random workstations are
  being audited, those users shall attend)
 Manager introduces you and explains purpose of audit and discusses
  his/her support for audit
 Auditor then takes control over meeting to discuss:
      Audit Scope/Objectives
      Auditor’s role
      Role of others
      Audit Process
      Timeframes: Make appointments with all parties you need to during
       the meeting.
 Take team approach: Do not offend anyone or play power games.
  People should be excited, not intimidated by you.
             Step 3: Fieldwork
 Auditor performs audit (often with worker)
 Report facts as you find them – as a detective would
 Even if the security breach is fixed when found, still
  report the breach and the fix
     Step 4: Report Preparation
 Include Scope/Purpose of audit
 Develop technical write-up of report first
    What organization does well
    What organization needs to do better
    If system administrator patched a hole, mention that
 Organize findings in a logical way.
 Write Executive Summary last
    Put Executive Summary as first section in Report
    Executive Summary should be understandable to non-technical
     executive manager
    Describe good and bad points in bullets (Make people look
     competent)
 Your report must be written professionally, if it is to be credible.
 Have another writer/auditor proofread
       Step 5: Exit Conference
 Auditor communicates findings to entire team
    Exit Conference Team = Entrance Conference Team
 Go over Executive Summary first
 Then give a copy of Audit Report to the team
 Team may defend themselves in meeting. Discussion
  (not argumentation) is healthy
 Amend report after meeting if new information arises
 Be careful in wording: “Best Practices include …” NOT
  “Most administrators know better than …”
 Stay out of arguments if you can
Step 6: Report to Management
 Prepare PowerPoint
  Presentation (Plan for 60
  minutes)
 Power Point should
  include:
   Audit purpose, scope,
    goals
   Executive Summary:
    Positive and Negative
    points
 Schedule 2-hour meeting
                Meeting Pointers
   Have highest executive schedule the meeting
   Highest executive kicks off the meeting. Auditor then takes over
   Give out copies of power point slides – executives love them
   Present for ½ hour
   Give full report out and take 15 minute break. This break gives
    mgmt a chance to talk to technical staff and ask questions
   After 15 minutes, start promptly again (or try to)
   Complete report
   Put a list of names of people who did exceptionally well – and
    should be encouraged and retained
   Answer additional questions when report is complete
    Additional Recommendations
 Clear up scope/purpose in one meeting (You will look unprofessional if you
    keep returning for clarification)
   Do not test/venture beyond what is agreed will be done. Extraneous
    information is not always welcome
   Do not go beyond scope – do not demonstrate vulnerabilities for legal reasons
   Always maintain a professional demeanor – not too chummy or informal
   Always have company representative present who is most knowledgeable about
    the matter being validated
   Company retains control: No surprises in tests, results
   Work together: Two heads are better than one
   Work with in-house expert. Involve them. Be humble
   Teach each other: Teach someone to fish is better than giving them a fish
   Discuss your findings with the in-house experts as you find them. There
    should be no surprises in the exit conference

 Oh yeah – dress well!
            Audit Report Outline
 Scope
 Audit Purpose
 Executive Summary
 Results
 References
         Audit Report Example
Scope:
 The company is interested in learning about their internet
  traffic at headquarters, including what applications are
  running, who is using which applications, and when. The
  company is also very interested in which web pages are
  being accessed both internally and externally. The time
  frame for measurement is one week.

Audit Purpose:
 Determine amount of traffic not related to business goals.
  Identify potential risks and additional controls.
      Audit Report Example (2)
Executive Summary:
 “At least M% of bandwidth is used for chat, external email,
  SSL, streaming media. N% of web references are for non-
  business use. External email is prone to viruses not
  protected by company email screeners. Most illegal web
  use comes from Building 205, 206 in particular, the Sales
  department.”

Recommendation:
 Block chat IP/port addresses in firewall.
 Train management on handling inappropriate use of time.
      Audit Report Example (3)
Results - Validation:
 This section shows line charts demonstrating usage for
  each protocol type per hour of working day (on average). It
  also shows pie charts showing usage of different categories
  of web page accesses. Actual results are provided in
  Appendix A.

Results –Verification:
 Best-in-class standards (i.e., COBIT) define that policies
  should be written and communicated to employees
  relating to what they can and cannot do [1]…
Changes for University Environment
 SANS recommends providing a technical summary
  of the results of the checklist tests.
 However, the professor needs to see more detail
 Each checklist item must describe:
  1) the procedure of how to measure the policy
  2) the outcome of the test
  3) any recommendations arising from the audit step.
 This technique allows the instructor and the
 organization to learn how the auditor arrived at his or
 her conclusions, and determine the validity of the
 report.
     Audit Report Example (4)
References:
 IT Control Objectives for Sarbanes-Oxley, 2nd Ed.,
  Exposure Draft, IT Governance Institute, April 30,
  2006.
How to Stay Out of Jail!
 Audits often require scanning a network to determine
  open ports, open applications.
 Results can include:
   Aborted production systems
   VERY upset administrators and managers


The difference between a hacker and a security analyst is
                     PERMISSION!!
Your written permission is your GET OUT OF JAIL card.
To stay out of jail and keep your job
 Plan to scan one subnet at a time! Pick an off-peak time in case something does go
  wrong.
 Get permission in Writing!
 Publicize the scan! The managers and system administrators must know the exact date
  and time of the scan.
 Eventually something will go seriously wrong, so always take precautionary steps.
 System administrators who go into panic mode for hours over your audit will not
  appreciate you!
 Be present! Be available for the entire duration of the scan, in case something does go
  wrong or you do get questions. Also, expect to answer questions up to a few days later.
 Be persistent! Be careful to check all devices within the scope. False positives and false
  negatives occur, so be extra careful.
 Provide Feedback! When the audit is complete, report to the system administrator or
  network manager and help them fix vulnerabilities. Complete the cycle within schedule,
  then begin scanning the next subnet.
 Note: If a host reboots due to an audit scan, it would have happened with a hacker – just
  a matter of time.
      Example Written Notice
Subject: Security Audit Tuesday Oct 10

Next Tuesday, Oct 10, from 4-6 PM we will be conducting an audit of
the firewall. We plan to validate the services that the firewall allows to
pass through, both inbound and outbound. As part of this audit’s
scanning process, a significant number of TCP and UDP packets will be
generated, and some ICMP packets. Specifically, we will be scanning
ports 1-NNNN with a UDP scan, a SYN half-open scan and a full tcp-
connect scan. In order to try to minimize any significant impact to the
firewall operations, we will generate packets slowly, at the rate of 1
packet every X seconds.

During the scan period, I will be available in room XXXX. I will also be
reachable via phone: 255-5466; via pager 262-445-9933; or email:
youraddress@cs.uwp.edu. I will be happy to reply to any questions or
concerns, and provide more detail about our audit if necessary.
        Summary & Conclusion
Stay out of Jail:
 Get signature on audit plan
 Broadcast what you plan to do when
 Only do what is in the audit plan

For this class:
 Be very specific about what tests you did and what results you got
 Be sure you have a member of the organization with when you do
  audit – allow them to see all problems at time of audit
 Double-check with me before submitting proposal or report to
  your customer – submit most professional document

				
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