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Network Assessment

How intrusion techniques contribute to system/network security Network and system monitoring System mapping Ports, OS, applications and purpose Network mapping Legal issues. Network Assessment. Network Monitoring. General Purpose Functions Applications Design

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Network Assessment

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  1. How intrusion techniques contribute to system/network security Network and system monitoring System mapping Ports, OS, applications and purpose Network mapping Legal issues Network Assessment

  2. Network Monitoring • General • Purpose • Functions • Applications • Design • NIDS – Network Intrusion Detection • IPS – Intrusion Prevention System

  3. Network and System Scanning • What application versions are running? • What services are running? • What ports/services are open? • What does the network look like? • What can the external world see? • Have any of these changed?

  4. Network Assessment • What do the other systems look like? • What does my system look like to outsiders? • Remote system characterization • LAN topology • Tools • nmap • nessus

  5. Network Assessment • Planning • Initial reconnaissance • System enumeration • Service enumeration • Vulnerability discovery

  6. Planning • Appropriate time • You will probably crash operational systems • You will need admin support • Approximate possible risks • Determine costs – man hours • Management written approval • Make sure every one buys into what you are doing

  7. Initial Reconnaissance • Corporate structure • Web surfing • Web browser • www.copernic.com • whois • host • NetScanTools Pro • DNS information • nslookup • DNS information • Should return minimal info if well configured

  8. System Enumeration • Using information from initial reconn phase • Discover more hosts and servers • Perimeter defense may block some scans • Directly probe target network • Combine discovery and analysis techniques • Structure of network • Perimeter design

  9. Tools • traceroute • The important info for this phase • Target routers and DNS servers • What is the route form a server to the Internet • Often server names give geographic or organizational info

  10. Tools • Network scanners • ICMP – fping and pinger • Looks for systems that return ICMP messages • TCP, UDP – nmap • Searches the entire range of IP addresses allocated to a network

  11. Service Enumeration • Now find out what is available on each system • Services • Ports open, ports filtered, OS • Application versions • System policies • Password policy • Users, domains, system names

  12. Tools • nmap • LANGuard • ww.gfisoftware.com/languard/lanscan.htm • Used as a LAN audit tool, $249 • Telnet and banner retrieval :\>telent sou.edu 22 SSH-1.99-OpenSSH_3.1p1 :\>telent www.sou.edu 80 HEAD / HTTP/1.0 HTTP/1.1 50` Method not implemented Date: Sun, 02 Mar 2003 20:46:44 GMT Server: Apache/1.3.27 (Unix) (Red Hat/Linux mod_ssl/2.8.12 OpenSSL/0.9.6 DAV/1.0.2 PHP/4.1.2 mod_perl/1.24

  13. Vulnerability Discovery • Vulnerability scanners • Work at the application layer • Most of these scanners also do network and port scanning • Best to start from the beginning • Network enumeration, System enumeration, Vulnerability discovery

  14. Vulnerability Discovery • Tools • Nessus – open sourced, very complete • ISS Internet Scanner – Windows, $$ • Retina – Windows, good GUI, $$

  15. Summary • Network assessment • CAREFUL • This is ILLEGAL

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