Transcript A+ Guide to Managing and Maintaining your PC, 6e

A+ Guide to Managing and
Maintaining your PC, 6e
Chapter 19
Securing Your PC and LAN
Objectives
• Learn how to secure a desktop or notebook
computer
• Learn how to secure a local wired or wireless
network
• Learn how malicious software works and how to
clean an infected system
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Introduction
• Topics to cover
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Methods for protecting computers and networks
How to use several security tools
How malicious software works
A step-by-step plan to remove malicious software
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Securing Your Desktop or Notebook
Computer
• Reasons for providing additional security
– Protection from attacks within the network
– Attacks through security loopholes
– Exposure during travel
• A few methods for securing a computer
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Limit use of the administrator accounts
Keep Windows updates current
Physically protect your equipment
Keep good backups of user data
Destroy trash that might contain sensitive data
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Access Control
• Authentication: identifies an individual
• Authorization: assigns privileges/rights to individuals
• Types of passwords
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Power-on passwords (configured in CMOS setup)
Windows passwords
Online account passwords
Application passwords
• Some rules for creating strong passwords
– Combine upper/lower case letters, numbers, symbols
– Do not use words in any language
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Figure 19-3 Set supervisor and user passwords in CMOS setup to
lock down a computer
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Access Control (continued)
• Controlling access to a PC using Windows
– Set a user password for the user account
– Configure user access to certain files and folders
• Overview for assigning permissions to file and folder
– Disable simple file sharing from View in Folder Options
– Open Properties window of a folder and select Sharing
– Click Permissions and select options
• Protected files and folders display authentication box
• Cacls: command for configuring file and folder access
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Figure 19-9 Control who can access a folder and the rights given that
user or user group
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Limit Use of the Administrator Account
• Three common types of accounts in Windows
– Administrator
– Guest
– Limited User
• Advice for protecting the Administrator Account
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Create a Limited User account for ordinary activities
Use Administrator account for reserved activities
Change appearance of desktop to flag the account
Change strong password on a regular basis
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Use a Personal Firewall
• Firewalls are implemented in software or hardware
• Purpose of a firewall
– Prevent worms or hackers from invading your system
• Turn on Windows Firewall to protect your system
– It may be configured to allow for exceptions
• Windows Firewall is included with Service Pack 2
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Figure 19-14 Use Windows Firewall to protect a Windows XP computer
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Use AV Software
• Antivirus (AV) software protects system from viruses
• Using AV software to greatest effect
– Configure software to automatically download updates
– Run AV software as a background process
– Set software to automatically scan e-mail attachments
• Virus signature: distinguishing characteristics of virus
• AV software does not always stop adware or spyware
• Use removal program for adware or spyware
– Example: Ad-Aware by Lavasoft (www.lavasoft.com)
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Figure 19-15 Set your AV software to stay current automatically
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Keep Windows Updates Current
• Causes for Windows susceptibility to attacks
– Popularity of system makes it an attractive target
– Highly integrated components give many entry points
• Update Web site: windowsupdate.microsoft.com
• Two ways to keep updates current
– Access Web site from Windows Update
– Run automatic update utility as background process
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Figure 19-16 Turn on Automatic Updates
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Set Internet Explorer for Optimum
Security
• Some security features in Internet Explorer
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Pop-up blocker
The ability to manage add-ons
The ability to block scripts
The ability to disable scripts embedded in Web pages
The ability to set the general security level
• Medium is recommended
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Figure 19-18 Control security settings for Internet Explorer
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Use Alternate Client Software
• Microsoft products targeted by authors of malware
– Microsoft Internet Explorer
– Microsoft Outlook Express and Microsoft Outlook
• Some reasons for susceptibility
– Popularity
– Close integration with other Windows components
– Use of ActiveX controls
• Alternate browser: Firefox by Mozilla
• Alternate e-mail client: Eudora by Qualcomm
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Consider Using Microsoft Shared
Computer Toolkit for Windows XP
• Microsoft Shared Computer Toolkit for Windows XP
– Locks down the drive on which Windows is installed
• Features of Windows XP that can be locked down
– Windows configuration
– Installed software or hardware
– User settings or user data
• Some temporary changes are allowed
– When system reboots, it returns to prior state
• Toolkit can be downloaded for free
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Hide and Encrypt Files and Folders
• Windows 2000/XP Encrypted File System (EFS)
– Works on with Windows 2000/XP NTFS EFS
– Is not supported in Windows XP Home Edition
• Encryption: technology for encrypting folders/files
• Best practice: encrypt at the folder level
• How to encrypt a file or folder
– Open Properties window of file or folder
– Click Advanced and select appropriate options
• Encrypted folders and files in are displayed in green
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Figure 19-21 Encrypt a file or folder using the Properties window
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Hide and Encrypt Files and Folders
(continued)
• Overview for sharing an encrypted file
– First export your certificate
– The other user imports certificate for access to file
• Sharing tool: Certificate Export Wizard
• Data recovery agent (DRA): can decrypt file/folder
• Three ways decrypt a file or folder
– Change encryption attribute from Properties window
– Move file or folder to a FAT logical drive
– Use the Cipher command
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Figure 19-27 A file is no longer encrypted when it is moved off the NTFS drive
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Physically Protect Your Equipment
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Don’t move or jar your computer when it’s turned on
Don’t smoke around your computer
If your data is private, keep it under lock and key
Keep magnets away from your computer
Lock down the computer case
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Beware of Social Engineering
• Social engineering
– Tricking people into giving out private information
– Passing unsafe programs into the network or PC
• Some techniques of social engineers
– Phishing: extracting personal data via e-mail
– Scam e-mail: offers to join phony ventures
– Virus (e-mail) hoax: clogs up e-mail systems
• A few rules for using the Internet
– Do not click links inside e-mail messages
– Investigate a Web site before downloading software
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Beware of Social Engineering
(continued)
• Two ways to debunk a hoax e-mail
– Note phrases/subjects that request mass forwarding
– Use services of security site; e.g., www.hoaxkill.com
• Scripts: code segments automating set of tasks
– Example: files with extensions .wsf and .vbs
• Malicious scripts are often hidden in e-mails
– Example: the link www.symantec.com.vbs
• Protecting against malicious scripts
– Set Windows to display file extensions
– Set Windows to first load script to Notepad
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Figure 19-28 An example of a hoax e-mail message
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Figure 19-30 Use the Edit File Type window to change the way Windows
displays and manages a file type
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Keep Good Backups of User Data
• Prepare for a disaster by making good data backups
• Refer to Chapter 13 for backup procedures
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Backup System Files
• Use Ntbackup to back up System State and registry
– Refer to Chapter 12 for procedures
• When to back up the System State
– After you have made major changes to the system
– Example: after installing a new hard drive
• Make backups a routine part of monthly maintenance
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Make Use of Event Logging and
Incident Reporting
• Some incidents you might be expected to report
– An attempt at breaking in to a secured PC or network
– The security has been broken
– An alarm has been activated
• Some reasons for incident reporting
– The need for others to respond to an incident
– The need to know about a weak security loophole
– Legal concerns
• Monitoring Windows 2000/XP logon events
– Configure Event Viewer to track failed logon attempts
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Figure 19-32 Event Viewer monitoring failures at logging on to Windows XP
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Make Use of Event Logging and
Incident Reporting (continued)
• Monitor changes to files and folders
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Set the Group Policy to audit an object
Add the users that you want to monitor
Decide which activity to monitor
View logged activity in the Event Viewer
• Some third-party monitoring tools
– Autoruns by Sysinternals
– WinPatrol by BillP Studios
• Monitoring network activity with Windows Firewall
– Configure Log Settings accessed from Advanced tab
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Figure 19-39 Using Windows Firewall, you can log dropped
packets and successful connections
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Destroy the Trash
• Trash is a source of sensitive information
• How to prevent the exposure of data
– Destroy all storage media before you throw it out.
– Destroy hard copies that contain sensitive data
– Steps to take when migrating from older medium
• Encrypt data being migrated between systems
• Control user access to migrated data
• Destroy old data storage medium no longer being used
– Erase hard-drive of old PC with a zero-fill utility
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Perform a Monthly Security
Maintenance Routine
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Change the administrator password
Make sure system is being automatically updated
Check that AV software is installed and current
Visually check the equipment for tampering
Check the Event Viewer
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Securing Your Wired or Wireless
Network
• Topics to cover
– How to use a router to secure a small network
– How to secure a wireless network
– Authentication techniques used for larger networks
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Use a Router to Secure a SOHO
Network
• SOHO: a small office or home office
• Use a router to secure a SOHO network
• Tasks that routers perform:
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Limit communication from outside the network
Limit communication from within the network
Secure a wireless access point
Implement a virtual private network (VPN)
• Keep router firmware current
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Authentication Technologies
• Controlling network access
– Encrypt user accounts/passwords at point of entry
– Decrypt user accounts/passwords before validation
• Popular authentication protocols: CHAP, Kerberos
• Two-factor authentication: present two types of id
• Smart cards
– Device with id information keyed or read into system
– Variations: key fob, magnetic strip, and USB smart cards
• Biometric data: id based on physical characteristics
– Some biometric devices: iris scanner, fingerprint reader
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Figure 19-41 For best security, keep your hardware firewall firmware updated
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Figure 19-42 A smart card such as this SecurID key fob is used to
authenticate a user gaining access to a secured network
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Dealing with Malicious Software
• Malicious software (malware or computer infestation)
– Any unwanted program intending harm to system
– Transmitted to your computer without your knowledge
• Examples of malware: viruses and worms
• Topics to cover
– How to recognize that a system is infected
– How to understand how malicious software works
– How to clean up the mess
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You’ve Got Malware
• Some signs of malicious messages
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Pop-up ads plague you when surfing the Web
Strange or bizarre error messages appear
Less memory than usual is available
Strange graphics appear on your computer monitor
The system cannot recognize the CD-ROM drive
Files constantly become corrupted
The OS boots, but cannot launch the Windows desktop
Your antivirus software displays one or more messages
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Here's the Nasty List
• Virus
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Program that replicates by attaching to other programs
Infected program must execute for virus to run
Example: boot sector program
Protection: run AV software in the background
Adware: produces all those unwanted pop-up ads
Spam is junk e-mail that you do not want
Spyware: program installing itself to spy on you
Worm: self-replicating program that overloads network
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Figure 19-46 The crash virus appears to be destructive, making the
screen show only garbage, but does no damage to hard drive data
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Here's the Nasty List (continued)
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Browser hijacker: alters home page/browser settings
Dialer: dials phone number without your knowledge
Keylogger: tracks all your keystrokes
Logic bomb: dormant code triggered by an event
Trojan horse: disguises itself as a legitimate program
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Here's the Nasty List (continued)
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Boot sector: virus hides in the boot sector program
File virus: hides in executable (.exe, .com, or .sys)
Multipartite virus: combined boot sector and file virus
Macro virus: hides in documents of macro files
Script virus: a virus that hides in a script
• How malware replicates and hides
– Uses various techniques to load itself into memory
– Attempts to hide from AV software
– Example: stealth virus manipulates its storage file
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Step-by-Step Attack Plan
• Run reputable AV software
– Examples: Norton Anti-Virus and McAfee VirusScan
• Run adware or spyware removal software
– Example: Windows Defender by Microsoft
• Search out and destroy what’s left
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Respond to any startup errors
Delete malicious files
Purge restore points
Clean the registry
Root out rootkits
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Figure 19-57 Results of running Windows Defender by Microsoft
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Summary
• Protect accounts and applications with passwords
• File and folders can be configured for selective
permissions
• Standard security tools: AV software, firewalls,
Windows Update
• Encryption technology: Windows 2000/XP NTFS EFS
• Techniques used by social engineers: phishing, scam
e-mails, virus hoaxes
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Summary (continued)
• Some events to monitor: failed logon access attempts
and network activity
• Use a router to secure a SOHO network
• Security techniques for larger networks: smart cards,
authentication protocols, biometric devices
• Malware: invasive programs such as viruses and
worms
• If AV software cannot clean or delete malware, use
other techniques such as deleting file from directory
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