ee579t/7 #1 spring 2003 © 2000-2003, richard a. stanley wpi ee579t network security 7:...

Spring 2003© 2000-2003, Richard A. Stanley

WPI EE579T/7 #1

EE579TNetwork Security

7: Vulnerability Assessment

Prof. Richard A. Stanley


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Overview of Tonight’s Class

• Review last week’s lesson

• Look at network security in the news

• Vulnerability assessment


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Last time...• SSL provides a means for secure transport layer

communications in TCP/IP networks

• SSL is a commonly used protocol, developed by Netscape, but ubiquitously used in browsers, etc.

• The key element of SSL is the handshake protocol

• SET not widely used for credit transactions, but the dual signature it introduced is useful


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Network Security Checklist(searchSecurity.com)

• Check systems for zombie agent software

• Minimize external exposure by minimizing Internet access and connectivity [do not leave non-mission critical Internet connections open continuously and deny Internet access to employees who do not need it.]

• Review security policies and ensure that they are current, implemented and enforced.


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Security checklist - 2

• Ensure all current service-level and security patches have been installed on operating systems and software, including antivirus updates

• Enhance the review and monitoring of all critical system logs for suspect activity, and consider implementing an intrusion-detection system

• Revisit firewall configurations and rules to ensure that unnecessary ports and services are turned off and that access control is tightly managed


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Security checklist - 3• Consider curtailing remote access by employees,

business partners, customers and consultants to essential business.

• Consider changing passwords for all super-user or power IDs such as Root, dbadmin, application manager IDs, etc., especially if that information has become widely shared. (emphasis added)

• Revisit access control lists to ensure that access to critical functions and resources is limited.


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• Discuss with your ISP what measures they are taking to ensure the security and reliability of the services they are providing you.

• Regularly back up all critical systems and test actual systems recovery procedures .

• Consider an incident response plan for addressing actions to be taken should a debilitating cyber-incident/event occur, affecting your business.


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• Ensure all users of your corporate computer systems (including employees, consultants, contractors and temporary workers) understand the importance of protecting the business and their role in the overall program.

• Users working from home via high-speed, broadband connections should be required to have a firewall installed on their system. In addition, they should only be allowed to connect to the corporate network through a VPN tunnel.


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What do all these security issues have in common?


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Thought for the Day

“The network is the computer.”

Sun Microsystems


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Is this quote for real or is it for marketing?

• What is typical PC bus speed?

• What sort of network data transfer rates can be attained?

• What does this mean for the future of networked computing?


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How To Rob a Bank

• Just walk in and demand the money– Where is the bank?– How do you know there is any money?– Where to park the getaway car?– Are there any guards or surveillance devices?– Will you need a disguise?– What kinds of things might go wrong?– What if they say “NO?”


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Success Requires Planning

• Whether robbing a bank or breaching network security, you need to plan ahead

• Planning ahead is known as vulnerability assessment– Acquire the target (case the joint)– Scan for vulnerabilities (find the entry points)– Identify poorly protected data (shake the doors)


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Information in Plain Sight

• Lots of valuable information is just lying around waiting to be used– telephone directories– company organization charts– business meeting attendee lists– promotional material

• The Internet has made having a company web page the measure of being “with it”


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Target: FBI


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?


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You get the idea• There is a lot of information out there, and it is

readily available to anyone• Good intelligence usually consists of open

source material properly collated• Law enforcement used to have special access to

this sort of information--now it’s out on the ‘net• Network access speeds up the rate at which

good intelligence can be collected


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Determine Your Scope

• Check out the target’s web page– physical locations– related companies or entities– merger/acquisition news– phone numbers, contact information– privacy or security policies– links to other related web servers– check the HTML source code


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Refine Your Search

• Run down leads from the news, etc.– Search engines are a good way

• FerretSoft

• Dogpile

– Check USENET postings– Use advance search capabilities to find links

back to target• Search on wpi + security gives ~ 2900 hits


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Use the Government

• EDGAR– SEC site (www.sec.gov/edgarhp.htm)– Search for 10-Q and 10-K reports– Try to find subsidiary organizations with

different names

• Think about what your organization has on databases available to the public


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Zero In On The Networks

• InterNIC– Organization– Domain– Network– Point of contact

• www.networksolutions.com

• www.arin.net


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Registrant:Worcester Polytechnic Institute (WPI-DOM) 100 Institute Road Worcester, MA 01609-2280 US

Domain Name: WPI.EDU

Administrative Contact, Billing Contact: Johannesen, Allan E (AEJ5) [email protected] The College Computer Center Worcester Polytechnic Institute 100 Institute Road Worcester, MA 01609-2280 508 754-3964 (FAX) 508-831-5483 (FAX) 508-831-5483 Technical Contact: Brandt, Joshua (JBC740) [email protected] Solipsist Nation 9 Circuit Ave. E Apt 1 Worcester, MA 01603 US 508-831-5512

Record last updated on 05-Dec-2000. Record created on 22-Mar-1988. Database last updated on 15-Feb-2001 02:07:04 EST.

Domain servers in listed order:

NS.WPI.EDU 130.215.24.1 NS1.YIPES.COM 209.213.223.126 NS2.YIPES.COM 209.50.39.102 NS3.YIPES.COM 209.50.40.102

Search for wpi.edu


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Other Sources

• InterNIC has 50-record limit, so…– ftp://rs.internic.net/domain– http://samspade.org/ssw/

• freeware

– www.nwpsw.com• Netscan tools

• Single copy price = $32.00

– www.ipswitch.com• WS_Ping ProPack = $37.50


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Example: Sam Spade

Sam Spade FeaturesEnvironmentEach tool displays it's output in it's own window, and everything is multi-threaded so you don't need to waitfor one query to complete before starting the next oneSome functions are threaded still further to allow lazy reverse DNS lookups (never do a traceroute -n again)The output from each query is hotlinked, so you can right click on an email address, IP address, hostnameor internic tag to run another query on itAppending the results of a query to the log window is a single button functionThere's a lot of online help, in both WinHelp and HTMLHelp formats. This includes tutorials, backgroundinformation and links to online resources as well as the program manual itself

Toolsping nslookup whois IP block whoisdig traceroute finger SMTP VRFYweb browser keep-alive DNS zone transfer SMTP relay checkUsenet cancel check website download website search email header analysisEmail blacklist query Abuse address query S-Lang scripting Time


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Query on Found Data

• POC– May be (often is) POC for other domains

• Query for email addresses -- here are a few from @wpi.edu

Amiji, Murtaza (MA3608) [email protected] (508) 831-5395 Baboval, John (JBJ116) [email protected] XXX-XXXX Ballard, Richard (RBS722) [email protected] 508-831-6731 Barnett, Glenn S (GSB14) [email protected] (315)475-5920 Bartelson, Jon (JB12891) [email protected] (508) 831-5725 (FAX) (508) 831-5483 Berard, Keith (KB2414) [email protected] (508)754-4502 Blank, Karin (KBJ257) [email protected] 203-762-0532 Blomberg, Adam (AB5417) [email protected] 508-755-7699


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Query the DNS

• Insecure DNS configuration can reveal information that should be kept confidential

• Zone transfers are popular attack methodologies– nslookup often used– pipe output to a text file– review the text file at your leisure– select potential “good targets” based on data


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Map the Network

• traceroute– Unix and Win/NT– tracert in NT for file name legacy reasons– Shows hops from router to destination

• Graphical tools exist, too– VisualRoute– www.visualroute.com


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Detailed Scanning

• Network ping sweeps– Who is active?– Automated capabilities with some tools

• ICMP queries– Reveal lots of information on systems

• System time

• Network mask


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Port Scanning

• Identify running services

• Identify OS

• Identify specific applications of a service

• Very popular

• Very simple

• Very dangerous


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Port Scan Types• Connect Scan--completes 3-way handshake• SYN--should receive SYN/ACK• FIN--should receive RST on closed ports• Xmas tree--sends FIN, URG, PSH; should receive

RST for closed ports• Null--turns off all flags; target should send back

RST for closed ports

• UDP--port probably open if no “ICMP port unreachable” message received


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Identify Running Services

• Strobe

• Udp_scan (from SATAN)

• netcat

• PortPro & Portscan

• nmap

• Using SYN scan is usually stealthy

• Beware of DoS results


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OS Detection, etc.

• Stack fingerprinting– Different vendors interpret RFCs differently

• Example:– RFC 793 states correct response to FIN probe is none– Win/NT responds with FIN/ACK

• Based on responses to specific probes, possible to make very educated guesses as to what OS running

– Automated tools to make this easy!• Nmap www.insecure.org/nmap/• Retina www.eeye.com/html/Products/Retina/


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Enumeration

• Try to identify valid user accounts on poorly protected resource shares– Windows NT

• net view– lists domains on network

– can also list shared resources

• nltest -- identifies PDC & BDC

• SNMP

• open a telnet connection


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Automated, Graphical Tools

• Can trace network topology very accurately– ID machines by IP, OS, etc.– Makes attack much easier

• Cheops– www.marko.net/cheops/

• Tkined– wwwhome.cs.utwente.nl/~schoenw/scotty/


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Summary

• Attacking a network is no different from robbing a bank; you have to plan if you expect to be successful

• There are three basic steps to planning, which is called vulnerability assessment:– Acquire the target (case the joint)

– Scan for vulnerabilities (find the entry points)

– Identify poorly protected data (enumeration)

• This applies if you are inside or outside the protected perimeter!


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Homework - 1

1. Identify and describe how you would enumerate resources on a Unix network, similar to the discussion in class of enumeration on Windows/NT

2. You are the network administrator. How would you defend against the threats of target acquisition and vulnerability scanning?

ee579t/7 #1 spring 2003 © 2000-2003, richard a. stanley wpi ee579t network security 7:...

Documents

stanley slide

stanley wpi security

stanley wpi wh

security patches

useful slide

managed slide

review security policies

critical systems