The OWASP Foundation
http://www.owasp.org
Why hackers don’t care about
your firewall
Seba Deleersnyder
seba@owasp.org
Sebastien Deleersnyder?
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5 years developer experience
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11 years information security experience
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Managing Technical Consultant
SAIT Zenitel
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Belgian OWASP chapter founder
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OWASP board member
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www.owasp.org
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Co-organizer www.BruCON.org
OWASP World
OWASP is a worldwide free and
open community focused on
improving the security of
application software.
Everyone is free to participate in
OWASP and all of our materials
are available under a free and
open software license.
Our mission is to make
application security visible so
that people and organizations
can make informed decisions
about application security risks.
The OWASP Foundation is a
501c3 not-for-profit charitable
organization that ensures the
ongoing availability and support
for our work.
Myth
We are secure because we have a firewall
75% of Internet Vulnerabilities are at Web
Application Layer *
*Gartner Group (2002 report)
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Source: Jeremiah Grossman, BlackHat 2001
20th century technology
Security evolution?
Source: Gunnar Peterson (Arctec Group)
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A firewall friendly protocol
=
“a skull friendly bullet”
(Bruce Schneier)
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Billing
Human Resrcs
Directories
APPLICATION
ATTACK
Web Services
Custom Developed
Application Code
Legacy Systems
Databases
Application Layer
Your security “perimeter” has huge holes at the
application layer
Web Server
Hardened OS
Firewall
Firewall
Network Layer
App Server
You can’t use network layer protection (firewall, SSL, IDS, hardening)
to stop or detect application layer attacks
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OWASP Top 10
A1 – Injection
Injection means…
• Tricking an application into including unintended commands in the data sent to
an interpreter
Interpreters…
• Take strings and interpret them as commands
• SQL, OS Shell, LDAP, XPath, Hibernate, etc…
SQL injection is still quite common
• Many applications still susceptible (really don’t know why)
• Even though it’s usually very simple to avoid
Typical Impact
• Usually severe. Entire database can usually be read or modified
• May also allow full database schema, or account access, or even OS level access
example : SQL-injection attack
https
User
User Database
Web Server
Application Server
Select user_information
from user_table
where username=’input username’ and
password=’input password’
Select user_information
from user_table
where username=’’ or 1=1 -– ‘ and
password=’abc’
RockYou?
December 2009
•
a hacker used SQL Injection techniques
to hack the database of RockYou
•
RockYou creates applications for
MySpace, Facebook, ...
Result
•
data of 32.603.388 users and
administrative accounts was
compromised (credentials +
clear text passwords)
•
the data also contained
email-addresses and passwords
for 3rd party sites
Question: how many of those users use the same password for other sites
too?
A2 – Cross-Site Scripting (XSS)
Occurs any time…
• Raw data from attacker is sent to an innocent user’s browser
Raw data…
• Stored in database
• Reflected from web input (form field, hidden field, URL, etc…)
• Sent directly into rich JavaScript client
Virtually every web application has this problem
• Try this in your browser – javascript:alert(document.cookie)
Typical Impact
• Steal user’s session, steal sensitive data, rewrite web page, redirect user to
phishing or malware site
• Most Severe: Install XSS proxy which allows attacker to observe and direct all
user’s behavior on vulnerable site and force user to other sites
XSS = Cross-site Scripting
Web application vulnerability
Injection of code into web pages viewed by others
XSS = new buffer overflow
Javascript = new Shell Code
XSSED.ORG
Still not fixed (with redirection):
http://www.google.com/search?btnI&q=allinurl:http://www.xssed.com/
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Browser Exploitation Framework
A3 – Broken Authentication and Session Management
HTTP is a “stateless” protocol
• Means credentials have to go with every request
• Should use SSL for everything requiring authentication
Session management flaws
• SESSION ID used to track state since HTTP doesn’t
• and it is just as good as credentials to an attacker
• SESSION ID is typically exposed on the network, in browser, in logs, …
Beware the side-doors
• Change my password, remember my password, forgot my password, secret
question, logout, email address, etc…
Typical Impact
• User accounts compromised or user sessions hijacked
Session Fixation Attack
A4 – Insecure Direct Object References
How do you protect access to your data?
• This is part of enforcing proper “Authorization”, along with
A7 – Failure to Restrict URL Access
A common mistake …
• Only listing the ‘authorized’ objects for the current user, or
• Hiding the object references in hidden fields
• … and then not enforcing these restrictions on the server side
• This is called presentation layer access control, and doesn’t work
• Attacker simply tampers with parameter value
Typical Impact
• Users are able to access unauthorized files or data
Insecure Direct Object References Illustrated
https://www.onlinebank.com/user?acct=6065
Attacker notices his acct
parameter is 6065
?acct=6065
He modifies it to a nearby
number
?acct=6066
Attacker views the victim’s
account information
A5 – Cross Site Request Forgery (CSRF)
Cross Site Request Forgery
• An attack where the victim’s browser is tricked into issuing a command to a
vulnerable web application
• Vulnerability is caused by browsers automatically including user authentication
data (session ID, IP address, Windows domain credentials, …) with each request
Imagine…
• What if a hacker could steer your mouse and get you to click on links in your
online banking application?
• What could they make you do?
Typical Impact
• Initiate transactions (transfer funds, logout user, close account)
• Access sensitive data
• Change account details
CSRF Illustrated
page 23
CSRF Illustrated
Good Saturday for Orkut Users
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A6 – Security Misconfiguration
Web applications rely on a secure foundation
• All through the network and platform
• Don’t forget the development environment
Is your source code a secret?
• Think of all the places your source code goes
• Security should not require secret source code
Configuration Management must extend to all parts of the application
• All credentials should change in production
Typical Impact
• Install backdoor through missing network or server patch
• XSS flaw exploits due to missing application framework patches
• Unauthorized access to default accounts, application functionality or data, or unused but
accessible functionality due to poor server configuration
Communication
Knowledge Mgmt
E-Commerce
Bus. Functions
Administration
Transactions
Accounts
Finance
Security Misconfiguration Illustrated
Datab
ase
Custom Code
App Configuration
Framework
Development
App Server
QA Servers
Web Server
Hardened OS
Insider
Test Servers
Source Control
Serving up malware
A quick Google Safe Browsing search of TechCrunch Europe's site shows suspicious activity twice over the last 90 days.
"Of the 128 pages we tested on the site over the past 90 days,
58 page(s) resulted in malicious software being downloaded and installed without user consent.”
(sep 2010)
Reason: unpatched WordPress
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A7 – Failure to Restrict URL Access
How do you protect access to URLs (pages)?
• This is part of enforcing proper “authorization”, along with
A4 – Insecure Direct Object References
A common mistake …
• Displaying only authorized links and menu choices
• This is called presentation layer access control, and doesn’t work
• Attacker simply forges direct access to ‘unauthorized’ pages
Typical Impact
• Attackers invoke functions and services they’re not authorized for
• Access other user’s accounts and data
• Perform privileged actions
Failure to Restrict URL Access Illustrated
https://www.onlinebank.com/user/getAccounts
Attacker notices the URL
indicates his role
/user/getAccounts
He modifies it to another
directory (role)
/admin/getAccounts, or
/manager/getAccounts
Attacker views more accounts
than just their own
A8 – Insecure Cryptographic Storage
Storing sensitive data insecurely
• Failure to identify all sensitive data
• Failure to identify all the places that this sensitive data gets stored
• Databases, files, directories, log files, backups, etc.
• Failure to properly protect this data in every location
Typical Impact
• Attackers access or modify confidential or private information
• e.g, credit cards, health care records, financial data (yours or your customers)
• Attackers extract secrets to use in additional attacks
• Company embarrassment, customer dissatisfaction, and loss of trust
• Expense of cleaning up the incident, such as forensics, sending apology letters, reissuing thousands of
credit cards, providing identity theft insurance
• Business gets sued and/or fined
Encrypt customer data?
customer data, 77 Million compromised.
(potentially CCs as well)
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A9 – Insufficient Transport Layer Protection
Transmitting sensitive data insecurely
• Failure to identify all sensitive data
• Failure to identify all the places that this sensitive data is sent
• On the web, to backend databases, to business partners, internal communications
• Failure to properly protect this data in every location
Typical Impact
• Attackers access or modify confidential or private information
• e.g, credit cards, health care records, financial data (yours or your customers)
• Attackers extract secrets to use in additional attacks
• Company embarrassment, customer dissatisfaction, and loss of trust
• Expense of cleaning up the incident
• Business gets sued and/or fined
Still not using SSL?
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A10 – Unvalidated Redirects and Forwards
Web application redirects are very common
• And frequently include user supplied parameters in the destination URL
• If they aren’t validated, attacker can send victim to a site of their choice
Forwards (aka Transfer in .NET) are common too
• They internally send the request to a new page in the same application
• Sometimes parameters define the target page
• If not validated, attacker may be able to use unvalidated forward to
bypass authentication or authorization checks
Typical Impact
• Redirect victim to phishing or malware site
• Attacker’s request is forwarded past security checks, allowing
unauthorized function or data access
Jobs by CNN?
http://ads.cnn.com/event.ng/Type=click&Redirect=http:/bit.ly/cP–XW
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Download
http://www.owasp.org/index.php/Top_10
CAN WE WIN THE WAR ON INSECURE
SOFTWARE?
Enter the rest of OWASP
People
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Education
Guides (build, test, code review)
Events
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Tools
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Requirements list
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Process
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Software Assurance Maturiy Model
(SAMM)
SAMM Security Practices
• The Security Practices cover all areas relevant to
software security assurance
• Each one is a ‘silo’ for improvement
Build “Your” Roadmap
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Gap analysis:
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Capturing scores from detailed assessments
versus expected performance levels
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Demonstrating improvement
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Capturing scores from before and after an
iteration of assurance program build-out
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Ongoing measurement
To make the “building blocks” usable, SAMM
defines Roadmaps templates for typical kinds of
organizations
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www.owasp.org
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OWASP NEAR YOU
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Upcoming local events
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OWASP Chapter meetings:
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23-May - Brussels:
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The Ghost of XSS Past, Present and Future – A Defensive Tale (by Jim
Manico, Infrared Security)
16-Jun - Brussels:
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The OWASP AppSensor Project (by Colin Watson, Watson Hall Ltd)
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How to become Twitter's admin: An introduction to Modern Web
Service Attacks (by Andreas Falkenberg, RUB)
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OWASP AppSec Europe – Dublin – Jun 7-9
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BruCON – Brussels – Sep 19-22
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OWASP BeNeLux – Luxembourg Nov-30/Dec-1
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