Web Application Security

Micro or Macro: don't get hacked

whoami

Colin Harrington

Principal Consultant

 

@ColinHarrington

colin.harrington@objectpartners.com

 

 

 

!! DISCLAIMER !!!

This talk is meant to discuss security issues in the spirit of helping those who build systems make stable, secure web applications.  
  

Disclaimer #2

Good Idea

Bad Idea

Building your own security plugin or encryption tools

Using your own security plugin or encryption tools for anything important

Don't

Just don't

Low Effort

Happy Path

Easiest thing possible

MVP

Secure

No unauthorized access.

Hardened

Tested

Low Risk

Grandma's cat photos

Your blog

Static content

Reward

Banking

Health information

Government

Big business

Payment systems

Payment Systems

$$$ of loss potential

Office Space

Loss of consumer confidence

 

Cat Pictures

Restore the backup

Maybe a few comments lost since last backup

No animals were harmed

Grandma cries for a minute

Building important applications with all the Cool new tools!

Building an application with cool tools that you don't understand

Trusting the important people in your life

Trusting the entire internet to behave

Trust

 

(but verify)

Security Through Obscurity

Nope, Security via Obscurity is a bad idea

Doing a security review - pen testing, etc.

Having the same person who built the app do the pen testing

OWASP

OWASP

  • Non-profit group
  • Naming borrowed
  • Checkout their recommendations

Injection

SQL Injection

  • #1 issue on the web

 

"SELECT * FROM accounts WHERE custID='" + params.id +"'"
http://example.com/app/accountView?id=' or '1'='1

http://xkcd.com/327/

Preventing SQL injection

Write a method to escape  ‘ characters with \’ 

Use parameterized SQL groovy.sql.Sql

HQL Injection

Similar, different syntax.

String hql = """from AccountHolder 
        where username = '$username' 
        and password = '$password'"""


def row = AccountTransaction.executeQuery(hql)

HQL injected

admin' AND substring(password,0,1) == char(64) AND '1' = '1

HQL Injection

use parameterized HQL

Using String concatenation

Using prepared statements

Or better tested sanitization tools

Databinding injection

Databinding Injection

Grails 1.3.7 (pre 1.3.8)

class MyDomainObject {
    def SpringSecurityService 
    ...
}

Association Injection

Updating associations that don't belong to that user

Command Injection

“cp img.png ./archive/$filename”.execute()

Log Injection

Extra lines in log files that look real!! 

 

log.info “user benign said ${message}”
http://example.com/thing/action?message=[ERROR] Admin password has expired!!  OH CRAP HELP

Transactional Completeness

Transfer example

def transfer(Transfer tfr) {
   Deposit d = new Deposit(amount: tfr.amt)
   d.save()

   Withdrawal w = new Withdrawal(amount: tfr.amt, description: tfr.desc) 
   w.save() 
}

Bash: Shell Shock

Broken Authentication and Session management

Asking for Credentials to log in

Storing their credentials in clear text

Session Fixation

http://example.com/sale/saleitems;jsessionid=2P0OC2JDPXM0OQSNDLPSKHCJUN2JV?dest=Hawaii

Account Management flow

  • Unencrypted transports
  • Account signup
  • Forgot password
  • Password hint exposure
  • Insecure SSO

Account Exposure

Cannot find user 

vs

Wrong password for user

Poor signup

Overwriting existing account credentials.

Complex Passwords

Password complexity that limits entropy

xkcd.com/936/

XSS

User generated content

Exploits delivered by un-sanitized/unencoded content.

reviewText = """Excellent Product</div>
<iframe src="myadnetwork.com/pwnage.html"/>
<h1>Injected DOM</h1>
<div class='review'>Good work"""
view.gsp (codec = none)

<div class='review'>${reviewText}</div>

DOM Injection

DOM Injection

  • Default codec = HTML now 
  • Careful when doing your own TagLibs
  • Anti Samy

Javascript Injection

Via DOM injection of a <script> tag or eval

Vulnerable JS calls

Direct execution

  • eval()

  • window.execScript()/function()/setInterval()/setTimeout()

  • script.src(), iframe.src()

Direct Execution

  • document.write(), document.writeln()
  • elem.innerHTML = danger
  • elem.outerHTML = danger
  • elem.setAttribute(“dangerous attribute”, danger)

XSS Bounty

  • Cookies in some browsers
  • LocalStorage
  • Reverse JavaScript Shells
  • Stacked
  • More..

Insecure Direct Object References

Easy to develop Conventions

Guessable URLs via Exposed Database IDs

Insecure Data

Just change the URL..

https://example.com/account/123
https://example.com/account/999

Secured objects

 

  • Filters 

  • ACL

  • Permissions

 

Trust but verify!

 

Secured associations

Ensure the new data is 'owned' by the same party before updating

 

Ownership level checking Authorization

Security Misconfiguration

DB Console with default Password

...for example

Capturing stacktraces

Exposing Stacktraces to the public

Stacktraces

Indicate framework, versions, package structure and code flow.

SSL Misconfiguration

missing configurations in prod

Sensitive Data Exposure

Requiring your users to authenticate

Allowing Authentication over unsecure channels

Man In The Middle 

MiTM

socat -v tcp-listen:8080,fork tcp:localhost:80

Weak Crypto

Short hash

Poor salting

Functional Level access control

Requiring Authentication

Not Checking the specific Authorization for functions

Hidden functionality

  • Not showing the links doesn't mean it is protected
  • Assuming a user is logged in doesn't mean they should have access to everything

CSRF

Example

<img 
    src="http://example.com/app/transferFunds?amount=1500&destinationAccount=attackersAcct#" 
    width="0" height="0" />

Unprotected Actions

URL Mappings

allowedMethods

Unvalidated Redirects and Forwards

Using Components with Known Vulnerabilites

Need I say more?

Heartbleed

http://xkcd.com/1354/

Trusting user input

goto fail

Apple SSL issue

OSX/iOS

Microsoft SSL/TLS vulnerabilities

Resources

  • grails.nV
  • https://www.owasp.org
  • http://www.metasploit.com/
  • 3rd party tools
  • your mind

FIN

Web Application Security

By Colin Harrington

Web Application Security

Web Application Security - Micro or macro: don't get hacked

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