www.it-ebooks.info www.it-ebooks.info NETWORK SECURITY HACKSTM www.it-ebooks.info Other computer security resources from O’Reilly Related titles Wireless Hacks BSD Hacks Knoppix Hacks Ubuntu Hacks Linux Desktop Hacks Linux Server Hacks Linux Server Hacks , Volume 2 Linux Multimedia Hacks Windows XP Hacks Windows Server Hacks Hacks Series Home hacks.oreilly.com is a community site for developers and power users of all stripes. Readers learn from each other as they share their favorite tips and tools for Mac OS X, Linux, Google, Windows XP, and more. Security Books Resource Center security.oreilly.com is a complete catalog of O’Reilly’s books on security and related technologies, including sample chapters and code examples. oreillynet.com is the essential portal for developers inter- ested in open and emerging technologies, including new platforms, programming languages, and operating systems. Conferences O’Reilly brings diverse innovators together to nurture the ideas that spark revolutionary industries. We special- ize in documenting the latest tools and systems, translating the innovator’s knowledge into useful skills for those in the trenches. Visit conferences.oreilly.com for our upcoming events. Safari Bookshelf (safari.oreilly.com) is the premier online reference library for programmers and IT professionals. Conduct searches across more than 1,000 books. Sub- scribers can zero in on answers to time-critical questions in a matter of seconds. Read the books on your Book- shelf from cover to cover or simply flip to the page you need. Try it today for free. www.it-ebooks.info NETWORK SECURITY HACKSTM SECOND EDITION Andrew Lockhart Beijing • Cambridge • Farnham • Köln • Paris • Sebastopol • Taipei • Tokyo www.it-ebooks.info Network Security Hacks ™ , Second Edition by Andrew Lockhart Copyright © 2007, 2004 O’Reilly Media, Inc. All rights reserved. Printed in the United States of America. Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472. O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles (safari.oreilly.com). For more information, contact our corporate/institutional sales department: (800) 998-9938 or corporate@oreilly.com. Editor: Brian Sawyer Production Editor: Philip Dangler Copyeditor: Rachel Wheeler Indexer: Ellen Troutman-Zaig Cover Designer: Karen Montgomery Interior Designer: David Futato Illustrators: Robert Romano and Jessamyn Read Printing History: April 2004: First Edition. November 2006: Second Edition. Nutshell Handbook, the Nutshell Handbook logo, and the O’Reilly logo are registered trademarks of O’Reilly Media, Inc. The Hacks series designations, Network Security Hacks, the image of barbed wire, and related trade dress are trademarks of O’Reilly Media, Inc. Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and O’Reilly Media, Inc. was aware of a trademark claim, the designations have been printed in caps or initial caps. While every precaution has been taken in the preparation of this book, the publisher and author assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. Small print: The technologies discussed in this publication, the limitations on these technologies that technology and content owners seek to impose, and the laws actually limiting the use of these technologies are constantly changing. Thus, some of the hacks described in this publication may not work, may cause unintended harm to systems on which they are used, or may not be consistent with applicable user agreements. Your use of these hacks is at your own risk, and O’Reilly Media, Inc. disclaims responsibility for any damage or expense resulting from their use. In any event, you should take care that your use of these hacks does not violate any applicable laws, including copyright laws. This book uses RepKover ™ , a durable and flexible lay-flat binding. ISBN 10: 0-596-52763-2 ISBN 13: 978-0-596-52763-1 [C] www.it-ebooks.info v Contents Credits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv Chapter 1. Unix Host Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. Secure Mount Points 2 2. Scan for SUID and SGID Programs 3 3. Scan for World- and Group-Writable Directories 5 4. Create Flexible Permissions Hierarchies with POSIX ACLs 5 5. Protect Your Logs from Tampering 9 6. Delegate Administrative Roles 11 7. Automate Cryptographic Signature Verification 13 8. Check for Listening Services 15 9. Prevent Services from Binding to an Interface 17 10. Restrict Services with Sandboxed Environments 19 11. Use proftpd with a MySQL Authentication Source 23 12. Prevent Stack-Smashing Attacks 26 13. Lock Down Your Kernel with grsecurity 28 14. Restrict Applications with grsecurity 33 15. Restrict System Calls with systrace 36 16. Create systrace Policies Automatically 39 17. Control Login Access with PAM 41 18. Restrict Users to SCP and SFTP 46 19. Use Single-Use Passwords for Authentication 49 20. Restrict Shell Environments 52 www.it-ebooks.info vi | Contents 21. Enforce User and Group Resource Limits 54 22. Automate System Updates 55 Chapter 2. Windows Host Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 23. Check Servers for Applied Patches 59 24. Use Group Policy to Configure Automatic Updates 63 25. List Open Files and Their Owning Processes 66 26. List Running Services and Open Ports 68 27. Enable Auditing 69 28. Enumerate Automatically Executed Programs 71 29. Secure Your Event Logs 73 30. Change Your Maximum Log File Sizes 73 31. Back Up and Clear the Event Logs 75 32. Disable Default Shares 78 33. Encrypt Your Temp Folder 79 34. Back Up EFS 80 35. Clear the Paging File at Shutdown 86 36. Check for Passwords That Never Expire 88 Chapter 3. Privacy and Anonymity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 37. Evade Traffic Analysis 91 38. Tunnel SSH Through Tor 95 39. Encrypt Your Files Seamlessly 96 40. Guard Against Phishing 100 41. Use the Web with Fewer Passwords 105 42. Encrypt Your Email with Thunderbird 107 43. Encrypt Your Email in Mac OS X 112 Chapter 4. Firewalling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 44. Firewall with Netfilter 117 45. Firewall with OpenBSD’s PacketFilter 122 46. Protect Your Computer with the Windows Firewall 128 47. Close Down Open Ports and Block Protocols 137 48. Replace the Windows Firewall 139 49. Create an Authenticated Gateway 147 50. Keep Your Network Self-Contained 149 www.it-ebooks.info Contents | vii 51. Test Your Firewall 151 52. MAC Filter with Netfilter 154 53. Block Tor 156 Chapter 5. Encrypting and Securing Services . . . . . . . . . . . . . . . . . . . . . . . 158 54. Encrypt IMAP and POP with SSL 158 55. Use TLS-Enabled SMTP with Sendmail 161 56. Use TLS-Enabled SMTP with Qmail 163 57. Install Apache with SSL and suEXEC 164 58. Secure BIND 169 59. Set Up a Minimal and Secure DNS Server 172 60. Secure MySQL 176 61. Share Files Securely in Unix 178 Chapter 6. Network Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 62. Detect ARP Spoofing 184 63. Create a Static ARP Table 186 64. Protect Against SSH Brute-Force Attacks 188 65. Fool Remote Operating System Detection Software 190 66. Keep an Inventory of Your Network 194 67. Scan Your Network for Vulnerabilities 197 68. Keep Server Clocks Synchronized 207 69. Create Your Own Certificate Authority 209 70. Distribute Your CA to Clients 213 71. Back Up and Restore a Certificate Authority with Certificate Services 214 72. Detect Ethernet Sniffers Remotely 221 73. Help Track Attackers 227 74. Scan for Viruses on Your Unix Servers 229 75. Track Vulnerabilities 233 Chapter 7. Wireless Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236 76. Turn Your Commodity Wireless Routers into a Sophisticated Security Platform 236 77. Use Fine-Grained Authentication for Your Wireless Network 240 78. Deploy a Captive Portal 244 www.it-ebooks.info viii | Contents Chapter 8. Logging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 79. Run a Central Syslog Server 251 80. Steer Syslog 252 81. Integrate Windows into Your Syslog Infrastructure 254 82. Summarize Your Logs Automatically 262 83. Monitor Your Logs Automatically 263 84. Aggregate Logs from Remote Sites 266 85. Log User Activity with Process Accounting 272 86. Centrally Monitor the Security Posture of Your Servers 273 Chapter 9. Monitoring and Trending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282 87. Monitor Availability 283 88. Graph Trends 291 89. Get Real-Time Network Stats 293 90. Collect Statistics with Firewall Rules 295 91. Sniff the Ether Remotely 297 Chapter 10. Secure Tunnels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 92. Set Up IPsec Under Linux 301 93. Set Up IPsec Under FreeBSD 306 94. Set Up IPsec in OpenBSD 309 95. Encrypt Traffic Automatically with Openswan 314 96. Forward and Encrypt Traffic with SSH 316 97. Automate Logins with SSH Client Keys 318 98. Use a Squid Proxy over SSH 320 99. Use SSH As a SOCKS Proxy 322 100. Encrypt and Tunnel Traffic with SSL 324 101. Tunnel Connections Inside HTTP 327 102. Tunnel with VTun and SSH 329 103. Generate VTun Configurations Automatically 334 104. Create a Cross-Platform VPN 339 105. Tunnel PPP 345 www.it-ebooks.info [...]... Network Security Hacks? This second edition of Network Security Hacks is a grimoire of 125 powerful security techniques This volume demonstrates effective methods for defending your servers and networks from a variety of devious and subtle attacks Within this book are examples of how to detect the presence (and track every keystroke) of network intruders, methods for protecting your network and data... done security consulting for small businesses in the area When he’s not writing books, he’s a senior security analyst with Network Chemistry, a leading provider of wireless security solutions Andrew is also a member of the Wireless Vulnerabilities and Exploits project’s (http://www.wirelessve.org) editorial board and regularly contributes to their wireless security column at NetworkWorld (http://www.networkworld.com/topics/wireless -security. html)... home network landscape and continue to gain traction in enterprise networks However, warding off unauthorized users and attackers poses a greater challenge in a wireless network While this chapter includes only a handful of hacks, what can be learned from them is invaluable Whether you want to share your network with others (but still maintain a semblance of security) or lock down your wireless network. .. Secure Software and a security authority who has been programming for nearly two decades In addition to coauthoring the O’Reilly books Secure Programming Cookbook for C and C++ and Network Security with OpenSSL, Matt coauthored the Safe C String Library (SafeStr), XXL, RATS, and EGADS • Ivan Ristic (http://www.modsecurity.org) is a web security specialist and the author of mod _security, an open source... (http://www.securesoftware.com) is Director of Security Services at Secure Software He consults in the fields of secure development and wireless security and is a coauthor of O’Reilly’s 802.11 Security book The results of his more recent investigations into Bluetooth security can be found at http://bluetooth.shmoo.com • Rob Flickenger (http://nocat.net) is a writer and editor for O’Reilly’s Hacks series He currently spends... their continued encouragement xiv | Credits www.it-ebooks.info 0 Preface Nowhere is the term hacker more misconstrued than in the network security field This is understandable because the very same tools that network security professionals use to probe the robustness of their own networks also can be used to launch attacks on any machine on the Internet The difference between system administrators legitimately... http:/ /hacks. oreilly.com xx | Preface www.it-ebooks.info Chapter 1 C H A P T E R O N E Unix Host Security Hacks 1–22 Networking is all about connecting computers together, so it follows that a computer network is no more secure than the machines that it connects A single insecure host can make lots of trouble for your entire network, because it can act as a tool for reconnaissance or a strong base of attack if... and other advanced security measures are useless if your servers offer easily compromised services Before delving into the network part of network security, you should first make sure that the machines you are responsible for are as secure as possible This chapter offers many methods for reducing the risks involved in offering services on a Unix-based system Even though each of these hacks can stand on... aspect of server security It’s also vital that traffic between the service and the clients connecting to it remain confidential in order to protect data and users’ authentication credentials This chapter shows how to do that for several popular services, such as SMTP, IMAP, POP3, Apache, and MySQL Chapter 6, Network Security Regardless of the operating system your servers use, if your network is connected... communications Networking protocols can be subverted in a number of powerful and surprising ways, leading to attacks that can range from simple denial of service to unauthorized access with full privileges This chapter demonstrates some tools and techniques used to attack servers using the network itself, as well as methods for preventing these attacks Chapter 7, Wireless Security Wireless networks have . Hacks Linux Desktop Hacks Linux Server Hacks Linux Server Hacks , Volume 2 Linux Multimedia Hacks Windows XP Hacks Windows Server Hacks Hacks. www.it-ebooks.info www.it-ebooks.info NETWORK SECURITY HACKSTM www.it-ebooks.info Other computer security resources from O’Reilly Related titles Wireless Hacks BSD Hacks Knoppix Hacks Ubuntu