Pentesting Using Burp Suite

Pentesting With Burp Suite
Taking the web back from automated scanners

Outline
 Intro to Web App Testing
 Scoping with Burp
 Mapping with Burp Spider, Intruder, and Engagement Tools
 Replacing Some good common methodology tasks
 Automated Scanner Breakdown
 Stealing from other tools and Modifying your Attacks
 Fuzzing with Intruder and FuzzDB
 Auth Bruting with Burp Intruder
 Random Burping...

Intro’s
 Jason Haddix
 Web App Pentester - HP Application Security Center
 Certs, blah, blah….
 @jhaddix

 Joel Parish
 Web App Pentester – HP Application Security Center
 Shoot web
 @jwpari

Web App Pentests!
 Process =
 Scoping -> Initial site recon, determine how large the
application is, how dynamic, try to assess platform, etc.
The age old question, engineer or sales guy?
 Pricing -> Use your scope to fit your assessment into a
pricing model. Usually by days of analysis.
 Analysis/Hacking -> Get your hack on. Usually good to
have a methodology.
 Reporting -> /sigh … I mean, SUPER IMPORTANT,
convey business risk, etc.

Burp Suite!
 Most commonly used interception proxy for web
hackery. Pay tool with Free Version.
 Comprised of several parts:
 Proxy – Intercept and Log Requests
 Spider – Discover Content
 Scanner – App Vuln Scanner
 Intruder – Attack Tool
 Repeater – Attack Tool
 Sequencer – Token Assessment
 Decoder & Comparer – Auxiliary Tools

Utilizing Burp in Process!
 Lets start with the
Process:
 Scoping: Defining the
range of the test. Leads
to pricing.
 Spidering gives us a site
map. We want to
determine application
complexity by how much
dynamic content there is.

Utilizing Burp in Process!
 Right click on your domain -> Engagement tools -> Analyze Target & Find
Scripts. (Spider 1st).

 This gives us a better idea (sometimes only pre-authentication) how to
budget/price the assessment. Spidering is not illegal. Throttle if necessary.
So easy even a sales guy can do it!

Utilizing Burp in Analysis!
 Analysis = Hackery
 Usually follows a “methodology”:
 Open Source Intelligence Gathering
 Mapping the target *
 Vulnerability Assessment & Fuzzing *
 Exploitation *
 Session Testing *
 Authentication Testing *
 Logic Testing
 Server Tests *
 Auxiliary tests (Flash, Java, ActiveX, Web Services)
 + more… many people do different things or do their tests in different
orders. *

Burp Intruder Payload Types
 Sniper – sends a single payload to each of the selected parameters; i.e. each parameter is
sequentially tested with the same set of variables

 Battering ram – sends a single payload to all of the selected parameters at once; i.e. all
parameters will be passed the first variable, followed by all Parameters being passed the
second variable, and so on until the payload is completed.

 Pitchfork – sends a specific payload to each of the selected parameters; i.e. all parameters
need to be passed its own payload, and the variables of each payload are passed to its
designated parameter in sequence.

 Cluster bomb – starts with a specific payload to each parameter, and when all variables have
been tested, will start testing with the payload from the next variable, such that all parameters
get tested with all variables

 For big lists use “runtime file” Payload set...

Burp Mapping!
 Burp Spider will discover all readily
available linked content. Make sure
you walk the app as well.
 We also want to indentify hidden or
non-linked content, normally using
tools like:
 Dirbuster (OWASP)
 Wfuzz (Edge Security)
 Burp Suite has its own functionality
for this!
 Right click on your domain ->
Engagement tools -> Discover Content

Burp Mapping!
 We can also steal Dirbuster’s and Wfuzz’s directory lists and
use them with Burp Intruder for better coverage if needed.
 Dirbuster has the best lists:

 Set up an intruder attack like so…

Burp Mapping!
Intruder - Burp can use Dirbuster/Wfuzz lists.
 - Right Click “/” and “Send to Intruder”
 - In the “Positions” tab Use Sniper Payload
 - Put the $$'s after “/”

 Under “Payloads” tab
 Use “Preset List” → Click “load” Choose

a Dirbuster List or wfuzz list.
 *** Quick tip, shutout the noise from other sites your browser is
interacting with by setting up a scope for the proxy tab: Right
Click your domain -> “add item to scope” -> Right click on the
filter bar -> show only in scope items… that’s better! ***

Burp Mapping++ !
Other mapping activities?
 Look for administrative portals
 We used to use a modified script: admin-scan.py
 Easily ported to burp intruder using the method on the last slide
 http://xrayoptics.by.ru/database/
 Tons of little scanners and useful tools here…

 Although not in this phase of the assessment server content
and vuln/server checks (a la Nikto) can be done this way!
 Now we move on…

Scanners!
 Scanners!
 Save time and money.

 Good first step in application security.

 Have lots of vetted code, attack strings, detection regex’s, auxiliary

tools, teams to support and update etc…

Scanners!
 Scanners
 Lots of application assessment is based around fuzzing application

input points.
 Bruteforce fuzzing vs intelligent fuzzing
 Identify input points

 Does this functionality display something back to the user?

 Does it interact with a database?

 Does it call on the server file system?

 Does it call on a URL or external/internal site/domain?

 Inject large amounts of arbitrary data (fuzzing) or inject large amounts of

relevant attacks strings (intelligent fuzzing)

 Predominantly this is what most scanners do… The kitchen sink approach.

Be a ninja… not a monkey
 If you’re a pentester… don’t be this:

Burp VA and Scanning!
 1st off Burp has it’s own scanner, so… win. (it’s pretty good)
 If web app scanners just use a grip of attack strings on
known input points, why cant we do this manually with Burp
Intruder?
 We most certainly can!

 Enter… the fuzzdb by
 ”Categorized by platform, language, and attack type, enumeration and attack patterns
have been collected into highly injectable fuzz payload lists. fuzzdb contains
comprehensive lists of attack payloads known to cause issues like OS command
injection, directory listings, directory traversals, source exposure, file upload bypass,
authentication bypass, http header crlf injections, and more. Since system responses
also contain predictable strings, fuzzdb contains a set of regex pattern dictionaries such
as interesting error messages to aid detection software security defects, lists of
common Session ID cookie names, and more.”

Fuzzdb!
Think of it as a set of ultimate web fu cheatsheets…

Fuzzdb!
 The fuzzdb gives us a good starting point… why not parse
and add all those open source scanner attack strings too?
(fuzzdb has done ‘some’ of this)
 Most of them are plaintext resource files that the scanners
call on… easy to parse and add to our modified fuzzdb.
 <.< >.> Shifty eyes…
 Keeping attacks separate via vector (SQLi, XSS, LFI/RFI,
etc…) allows us to make less requests because as humans
we know what type of attack we are looking to achieve and
we can limit Burp to that subset of attacks.
 Our set of attack strings + burp files will be released a few
days post con, or put directly into the fuzzdb trunk (whichever
happens 1st ;)

Interpreting fuzz results
 Usually when fuzzing we can use response size, return time, and regex’s to
look for fishy application behavior.
 Fuzzdb has a great Burp grep file:
 Open Burp Suite, go to the Intruder tab, and the Options sub-tab
 Look for the section "grep"
 Click "clear" to clear the existing listings in the list box
 Click "load" and load regex/errors.txt from your fuzzdb path, as below
 This will search all output pages generated by Intruder payloads for the extensive list of known
error strings, for later analysis.
 After successful identification, using Burp or auxiliary tools/scripts for
exploitation is easy…
 Filter Evasion? Old blacklists never learn new tricks =(
 http://www.wiretrip.net/rfp/txt/whiskerids.html
 http://www.securityaegis.com/filter-evasion-houdini-on-the-wire/

Burp Session Testing
 Usually session tokens from common frameworks are well vetted
but in instances where you see a custom session token fly by
Burp’s Sequencer can gather and test for entropy via all kinds of
compliance needs.
 Pretty reporting graphs.

Burp Auth Testing
 Bruteforcing Authentication with
Burp Intruder
 Attempt Login
 Go to Proxy History Tab
 Find the POST request
 Send to Intruder
 Use Cluster Bomb payload
 Clear all payload positions
 Mark username and password fields as
payload positions
 Goto “payloads” tab
 Set “payload set” 1 to your username list
 Set “payload set” 2 to your password list
 Click on the intruder Menu
 Start Attack
 Look for different lengths or grep possible
successful auth messages under options

Burp Auth Testing
 The password lists are non extensive!
 Go thank Ron, he makes Facebook cry:
 http://www.skullsecurity.org/blog/2010/the-ultimate-faceoff-

between-password-lists
 Huge password repository. Actual user data from hacked

sites:
 RockYou
 Phpbb
 Myspace
 Hotmail
 Hak5
 Facebook
 More…
 @iagox86

Random Burping Tips
 Burp Spider in conjunction
with - Engagement Tools →
Search makes Burp an IH
tool

 Find injected code or
javascript redirects when
inspecting a compromised
site/app.

Random Burping Tips
 Proxy Tab --> Options

 Disable clientside input
validation when testing via
the browser.

 Unhide hidden form fields.

 Thick Client testing – Proxy
-> options -> support invisible
mode

Turning Burp into an
Automated Scanner?
 Paul Haas’s (Foundstone) sodapop
tool uses Burp Headless to spider a
website and actively scan for
vulnerabilities, and to log everything
to stdout.
 (http://www.redspin.com/blog/2010/0
9/20/advanced-burp-suite-
automation-2/)

Turning Burp into an Automated
Scanner?

Turning Burp into an Automated
Scanner?

 W3af, awesome Python web attack framework
 So, now we have access to Burp scanners/proxy,
and a Python runtime. Why don’t we just import
w3af checks into burp?
(http://blog.ombrepixel.com/post/2010/09/09/Run
ning-w3af-plugins-in-Burp-Suite)

IBurpExtender
 Hooks into HTTP Request for
pre/post Burp processing
 Edit Burp configuration
pragmatically
 Send requests to repeater/intruder
 Access to scanning/proxy data

Eww Java
 Do I have to work with Java?
 -Xmn4096M -Xms4096M –Xmx4096M
 Java is fast now
 And the JVM is awesome

JVM
 Lets you leverage agile synergies to
arbitrate technical debt across
organizational and personal boundaries.

 WTF?

JVM – Write anything w/anything
 Ruby (JRuby)
 Python (Jython)
 Javascript (Rhino)
 Clojure
 Scala
 And Lua, PHP (Quercus), COBOL ಠ_ಠ and
dozens of other languages.

Burp Extensions in other
Languages
 http://github.com/emonti/buby (JRuby)
 http://blog.ombrepixel.com/public/burppytho
n_v0.1.zip (Jython)
 Write your own! (all of the above JVM
languages can use the IBurpExtender
interface)

Things humans aren’t good at
 I’m not a bit twiddling God
 GDS has done some great stuff with decompressing DEFLATE
and binary SOAP HTTP requests/responses.
 Using JRuby/Buby to attack Java Object Serialization
https://media.blackhat.com/bh-eu-
10/whitepapers/Saindane/BlackHat-EU-2010-Attacking-
JAVA-Serialized-Communication-wp.pdf

Things humans aren’t good at
 Padding Oracle vulnerabilities
 Write a Burp hook to decrypt ASP.net
viewstate with the machine key from the
extracted from padding oracles.
 Re-encrypt on exit
 Use Burp’s built-in viewstate editor, edit
flags and win!

Conclusions
 Manual testing wins
 Don’t be a tool, really
use your tools.
 Humans > machines

Links
 http://portswigger.net/burp/
 http://code.google.com/p/fuzzdb/
 http://www.skullsecurity.org/blog/2010/the-
ultimate-faceoff-between-password-lists
 Sectooladdict.blogspot.com

Closing Notes or Whatevs
Taking your mom back from automated scanners

Pentesting Using Burp Suite

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