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COEN 250

COEN 250. Security Threats. Network Based Exploits. Phases of an Attack Reconnaissance Scanning Gaining Access Expanding Access Covering Tracks. Reconnaissance. Social Engineering “I cannot access my email. What do I do?” Dumpster Diving (especially useful when people move)

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COEN 250

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  1. COEN 250 Security Threats

  2. Network Based Exploits Phases of an Attack • Reconnaissance • Scanning • Gaining Access • Expanding Access • Covering Tracks

  3. Reconnaissance • Social Engineering • “I cannot access my email. What do I do?” • Dumpster Diving (especially useful when people move) • Search the Web • Sam Spade (www.samspade.org/ssw/), CyberKit, NetScanTools, ... • Search Engine • Usenet postings • Whois

  4. Reconnaissance Databases • To research .com , .net, and .org domain names:InterNIC whois feature: www.internic.net/whois.html allwhois, network soultions, ... • ARIN: American Registry for Interent Numbers (www.arin.net/whoiis/arin-whois.html) • RIPE (Europe) www.ripe.net • APNIC (Asia Pacific) www.apnic.net

  5. Reconnaissance: Scanning Once we have a target, we need to get to know it better. Methods: • War Dialing (to find out modem access) • Network Mapping • Vulnerability Scanning • War Driving

  6. Scanning: War Dialing Purpose: Find a modem connection. • Many users in a company install remote PC software such as PCAnywhere without setting the software up correctly. • War Dialer finds these numbers by going through a range of phone numbers listening for a modem. • Demon Dialer tries a brute force password attack on a found connection. • Typically: war dialing will find an unsecured connection.

  7. Scanning: Network Mapping Ping: • ping is implemented using the Internet Control Message Protocol (ICMP) Echo Request. • A receiving station answers back to the sender. • Used by system administrators to check status of machines and connections.

  8. Scanning: Network Mapping Traceroute: • Pings a system with ICMP echo requests with varying life spans (= # of hops allowed). • A system that receives a package with expired numbers of hops sends an error message back to sender. • Traceroute uses this to find the route to a given system. • Useful for System Administration

  9. Scanning: Network Mapping Cheops: Network Scanner (UNIX based) (Uses traceroute and other tools to map a network.) Cheops et Co. are the reason that firewalls intercept pings.

  10. Reconnaissance: Port Scans • Applications on a system use ports to listen for network traffic or send it out. • 216 ports available, some for known services such as http (80), ftp, ... • Port scans send various type of IP packages to target on different ports. • Reaction tells them whether the port is open (an application listens).

  11. Reconnaissance: Nmap • Uses different types of packets to check for open ports. • Can tell from the reaction what OS is running, including patch levels. • Can run in stealth mode, in which it is not detected by many firewalls.

  12. Reconnaissance: Webserver Information Leakage • Most webservers leak information: • HTTP answers • Identify webserver • URLs • Have forms peculiar to certain webservers: • Extensions: • ASP pages: Probably IIS • “http://search.barnesandnoble.com/booksearch/results.asp?WRD=Oxford+history&z=y&cds2Pid=9481” • “htm”: Probably windows • Format of query string • Cookies

  13. Reconnaissance: Webserver Information Leakage • Most webservers leak information: • Error Messages • Identify webserver technology by name and version number. • Sometimes send debug information to browser. • Can be provoked by changing query strings or asking for non-existing resources. • Sometimes, possible to get a message from the database engine.

  14. Reconnaissance Prevention • Firewalls can make it very difficult to scan from the outside. • Drop scan packets. • Patched OS do not have idiosyncratic behavior that allows OS determination. • IDS can detect internal scans and warn against them.

  15. Gaining Access • Gain access using application and OS attacks. • Gain access using network attack.

  16. Gaining Access through Apps and OS • Trends: • Modularized super-tools • The Metasploit Project • multiple attacks • multiple payloads • easily updated • Buffer Overflow Attacks • Stack • Heap • Dynamic Memory Attacks • Format Vulnerabilities • Integer Overflow … • Password Attacks • Web Application Attacks

  17. Gaining Access:Web Application Attacks • The URL not only contains the web address of a site, but also input: http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=web+application+attack • A poorly written webpage allows the viewer to input data in an uncontrolled fashion. If the webpage contains SQL, the user might execute SQL commands.

  18. Gaining Access through Network Attacks: Sniffing • Sniffer: Gathers traffic from a LAN. • Examples: Snort www.snort.org, Sniffit reptile.rug.ac.be/~coder/sniffit/sniffit.html • To gain access to packages, use spoofed ARP (Address Resolution Protocol) to reroute traffic.

  19. Gaining Access: Session Hijacking • IP Address Spoofing: Send out IP packages with false IP addresses. • If an attacker sits on a link through which traffic between two sites flows, the attacker can inject spoofed packages to “hijack the session”. • Attacker inserts commands into the connection. • Details omitted.

  20. Exploiting and Maintaining Access After successful intrusion, an attacker should: • Use other tools to gain root or administrator privileges. • Erase traces (e.g. change log entries). • Take measures to maintain access. • Erase security holes so that no-one else can gain illicit access and do something stupid to wake up the sys. ad.

  21. Maintaining Access: Trojans • A program with an additional, evil payload. • Running MS Word also reinstalls a backdoor. • ps does not display the installed sniffer.

  22. Maintaining Access: Backdoors • Bypass normal security measures. Example: netcat • Install netcat on victim with the GAPING_SECURITY_HOLE option. C:\ nc -1 –p 12345 –e cmd.sh • In the future: connect to port 12345 and start typing commands.

  23. Maintaining Access: Backdoors • BO2K (Back Orifice 2000) runs in stealth mode (you cannot discover it by looking at the processes tab in the TASK MANAGER. • Otherwise, it is a remote control program like pcAnyWhere, that allows accessing a computer over the net.

  24. Maintaining Access: Backdoors • RootKit: A backdoor built as a Trojan of system executables such as ipconfig. • Kernel-Level RootKit: Changes the OS, not only system executables.

  25. Covering Tracks: • Altering logs. • Create difficult to find files and directories. • Covert Channels through Networks: • Loki uses ICMP messages as the carrier. • Use WWW traffic. • Use unused fields in TCP/IP headers.

  26. Hacker Damage • Releasing Information • Releasing Software • By circumventing copying protection. • Through IP theft • Consuming Unused(?) Resources • Discover and Document Vulnerabilities • Compromise Systems and Increase their Vulnerabilities • Website Vandalism

  27. Hacking Profile • Shift to for-profit motiv • Shift to underground economy

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