Lab 1 Reconnaissance Network Mapping and Vulnerability Assessment
Lab 1: Reconnaissance, Network Mapping, and Vulnerability Assessment • Reconnaissance • Scanning • Network Mapping • Port Scanning • OS detection • Vulnerability assessment 1
Reconnaissance • Internet Network Information Center who-is database www. internic. net/whois. html • Registrar’s database i. e. www. networksolutions. com • American Registry for Internet Numbers (ARIN) http: //www. arin. net/whois/ • Domain Name System (DNS) nslookup ECE 4112 - Internetwork Security 2
Reconnaissance • After Recon, it is possible to know detailed information about a potential target • This information includes specific IP addresses and ranges of addresses that may be further probed. ECE 4112 - Internetwork Security 3
Scanning Objective 1: Network Mapping Why: To determine what the network looks like logically. How: Manually using tools like ping, traceroute, tracert, or with tools like Cheops network mapping tool ECE 4112 - Internetwork Security 4
Scanning Objective 2: Port Scanning Why: To find open ports in order to exploit them. How: • TCP Connect -- attempt to complete 3 -way handshake, look for SYN-ACK, easy to detect this scan • TCP SYN Scan -- “half-open” scan, look for SYN-ACK, then send RESET, target system will not record connection, also faster than TCP connect scan • TCP FIN, Xmas Tree, Null Scans -- scans that violate the protocol, closed ports send RESET, open ports send nothing (Windows does not respond to these scans) ECE 4112 - Internetwork Security 5
Scanning • TCP ACK Scan -- may be useful to get past packet filters (believes it is a response to a request from inside firewall), if receive RESET, know this port is open through firewall • FTP Bounce Scan -- request that server send file to a victim machine inside their network (most servers have disabled this service) • UDP Scan -- unreliable, if receive ICMP Port Unreachable, assume closed, otherwise open • Ping Sweep -- can use ICMP or TCP packets ECE 4112 - Internetwork Security 6
Scanning Additional objectives: • Decoys -- insert false IP addresses in scan packets • Ping Sweeps -- identify active hosts on a target network • Find RPCs -- connect to each open port looking for common RPC services (send NULL RPC commands) ECE 4112 - Internetwork Security 7
Scanning Objective 3: Operating System Detection Why: To determine what Operating System is in use in order to exploit known vulnerabilities. • Also known as TCP stack fingerprinting. • Take advantage of ambiguity of how to handle illegal combinations of TCP code bits that is found in the RFCs. • Each OS responds to illegal combinations in different ways. • Determine OS by system responses. ECE 4112 - Internetwork Security 8
OS detection Window Size: Most Unix Operating Systems keep the window Size the same throughout a session. Windows Operating Systems tend to change the window size during a session. Time to Live: Free. Bsd or Linux typically use 64, Windows Typically uses 128. Do Not Fragment Flag: Most OS leave set, Open. BSD leaves it unset. ECE 4112 - Internetwork Security 9
Nmap: Network Exploration Tool Purpose: “To allow system administrators and curious individuals to scan large networks to determine which hosts are up and what services they are offering. ” Available at: http: //www. insecure. org/nmap/ ECE 4112 - Internetwork Security 10
Nmap: What does it do? • Port scanning • OS detection • Ping sweeps ECE 4112 - Internetwork Security 11
Nmap: How does it work? Use the following Scan techniques : • UDP • FIN • TCP connect() • ACK sweep • TCP SYN (half open) • Xmas Tree • ftp proxy (bounce attack) • SYN sweep • Reverse-Identification • IP Protocol • ICMP (ping sweep) • Null Scan ECE 4112 - Internetwork Security 12
Nmap: How does it work? • Uses the following OS detection techniques • TCP/IP fingerprinting • stealth scanning • dynamic delay and retransmission calculations • parallel scanning • detection of down hosts via parallel pings • decoy scanning • port filtering detection • direct (non-port mapper) RPC scanning • fragmentation scanning • flexible target and port specification. ECE 4112 - Internetwork Security 13
Scanning Vulnerability Assessment (1) Objective 4: Vulnerability Assessment Why: To determine what known (or unknown? ) vulnerabilities exist on a given network Vulnerabilities come from: • Default configuration weakness • Configuration errors • Security holes in applications and protocols • Failure to implement patches! ECE 4112 - Internetwork Security 14
Vulnerability Assessment Vulnerability checkers use: • Database of known vulnerabilities • Configuration tool • Scanning engine • Knowledge base of current scan • Report generation tool ECE 4112 - Internetwork Security 15
Scanning tool: Nessus Purpose: “To provide to the internet community a free, powerful, up-to-date and easy to use remote security scanner. ” Security Scanner: “A software which will audit remotely a given network and determine whether bad guys (aka 'crackers') may break into it, or misuse it in some way. ” Available platforms: UNIX for client and server Windows for client only Available at: http: //www. nessus. org/ ECE 4112 - Internetwork Security 16
Nessus: What does it do? • Iteratively tests a target system (or systems) for known exploitation vulnerabilities • Uses a separate plug-in (written in C or Nessus Attack scripting Language) for each security test • Can test multiple hosts concurrently • Produces a thorough vulnerability assessment report at the conclusion of the vulnerability scan ECE 4112 - Internetwork Security 17
What does Nessus check for? • Backdoors • Port scanners • CGI abuses • Remote file access • Denial of Service • RPC • Finger abuses • SMTP problems • FTP • Useless services • Gain a shell remotely • Windows • Gain root remotely • and more. . . ECE 4112 - Internetwork Security 18
Scanning tool: Superscan 4 (windows XP) Purpose: “To provide to the internet community a free, powerful, up-to-date and easy to use remote security scanner. ” Security Scanner: “Superior scanning speed, Support for unlimited IP ranges, Improved host detection using multiple ICMP methods , TCP SYN scanning , UDP scanning (two methods), IP address import supporting ranges and CIDR formats, Simple HTML report generation, Source port scanning, Fast hostname resolving, Extensive banner grabbing , Massive built-in port list description database , IP and port scan order randomization , A selection of useful tools (ping, traceroute, Whois etc) , Extensive Windows host enumeration capability. ” 19 ECE 4112 - Internetwork Security
Lab Enhancements What corrections and or improvements do you suggest for this lab? Please be very specific and if you add new material give the exact wording and instructions you would give to future students in the new lab handout. You may cross out and edit the text of the lab on previous pages to make minor corrections/suggestions. General suggestions like add tool xyz to do more capable scanning will not be awarded extras points even if the statement is totally true. Specific text that could be cut and pasted into this lab, completed exercises, and completed solutions may be awarded additional credit. Thus if tool xyx adds a capability or additional or better learning experience for future students here is what you need to do. You should add that tool to the lab by writing new detailed lab instructions on where to get the tool, how to install it, how to run it, what exactly to do with it in our lab, example outputs, etc. You must prove with what you turn in that you actually did the lab improvement yourself. Screen shots and output hardcopy are a good way to demonstrate that you actually completed your suggested enhancements. The lab addition section must start with the title “Lab Addition”, your addition subject title, and must start with a paragraph explaining at a high level what new concept may be learned by adding this to the existing laboratory assignment. After this introductory paragraph, add the details of your lab addition. Include the lab addition cover sheet from the class web site. ECE 4112 - Internetwork Security 20
Lab Enhancements Cover Sheet • What new concept may be learned by adding this to the existing laboratory assignment? (Or what existing concept is better learned with this addition as opposed to what is in the existing lab assignment): • What are the specific vulnerabilities this concept exploits and what are the defenses one can use against the vulnerabilities? Completion checklist: • Did you email an electronic copy of your laboratory addition to Henry within 24 hours after the class (and name the attachment Grx_Laby_Add. doc)? ____ • Did you prepare a 5 minute in class presentation (which includes enough theory and results to educate your classmates on what you did and how you did it and discuss defenses) and email that to Henry within 24 hours after the class (and name the attachment Grx_Laby_Add. ppt)? _______ • Did you include proof that you got this working in our laboratory with our equipment? (Screen shots, output, etc)? ______ • Did you include references and attributes for all materials that you used? _____ • Did you write your addition so that it does not require editing to cut and paste into the lab? ____ • Did you include answers to all questions you ask in the addition (a solution sheet)? _______ • In adding your new concepts/exercises did you include detailed lab instructions on where to get any software you may need, how to install it, how to run it, what exactly to do with it in our lab, example outputs proving that you got the enhancement to work in our lab? ______ • Did you include any theory/background and or fundamentals of the ideas and concepts behind this addition? _______ ECE 4112 - Internetwork Security 21
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