Transcript EE579T-Class 7B - Electrical & Computer Engineering

EE579T
Network Security
7: Vulnerability Assessment
Prof. Richard A. Stanley
Spring 2003
© 2000-2003, Richard A. Stanley
WPI
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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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WPI
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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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WPI
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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 nonmission 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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WPI
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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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WPI
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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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WPI
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Security checklist - 4
• 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 cyberincident/event occur, affecting your business.
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WPI
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Security checklist - 5
• 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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WPI
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What do all these security issues
have in common?
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WPI
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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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WPI
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How To Rob a Bank
• Just walk in and demand the money
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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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WPI
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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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© 2000-2003, Richard A. Stanley
WPI
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Information in Plain Sight
• Lots of valuable information is just lying
around waiting to be used
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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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WPI
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Determine Your Scope
• Check out the target’s web page
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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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WPI
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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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WPI
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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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WPI
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WPI
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Zero In On The Networks
• InterNIC
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Organization
Domain
Network
Point of contact
• www.networksolutions.com
• www.arin.net
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WPI
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Search for wpi.edu
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
NS1.YIPES.COM
NS2.YIPES.COM
NS3.YIPES.COM
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© 2000-2003, Richard A. Stanley
130.215.24.1
209.213.223.126
209.50.39.102
209.50.40.102
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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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WPI
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Example: Sam Spade
Sam Spade Features
Environment
Each tool displays it's output in it's own window, and everything is multi-threaded so you don't need to wait
for one query to complete before starting the next one
Some 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, hostname
or internic tag to run another query on it
Appending the results of a query to the log window is a single button function
There's a lot of online help, in both WinHelp and HTMLHelp formats. This includes tutorials, background
information and links to online resources as well as the program manual itself
Tools
ping
dig
web browser
Usenet cancel check
Email blacklist query
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© 2000-2003, Richard A. Stanley
nslookup
traceroute
keep-alive
website download
Abuse address query
WPI
whois
finger
DNS zone transfer
website search
S-Lang scripting
IP block whois
SMTP VRFY
SMTP relay check
email header analysis
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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© 2000-2003, Richard A. Stanley
WPI
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Query the DNS
• Insecure DNS configuration can reveal
information that should be kept confidential
• Zone transfers are popular attack
methodologies
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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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WPI
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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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WPI
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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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WPI
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Port Scanning
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Identify running services
Identify OS
Identify specific applications of a service
Very popular
Very simple
Very dangerous
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WPI
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Port Scan Types
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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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© 2000-2003, Richard A. Stanley
WPI
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Identify Running Services
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Strobe
Udp_scan (from SATAN)
netcat
PortPro & Portscan
nmap
Using SYN scan is usually stealthy
Beware of DoS results
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WPI
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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
• Retina
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© 2000-2003, Richard A. Stanley
www.insecure.org/nmap/
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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WPI
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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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© 2000-2003, Richard A. Stanley
WPI
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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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© 2000-2003, Richard A. Stanley
WPI
EE579T/7 #48
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?
Spring 2003
© 2000-2003, Richard A. Stanley
WPI
EE579T/7 #49