owasp appsec europe 2006 automated tools

Copyright © 2006 - The OWASP FoundationPermission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License.

The OWASP Foundation

OWASP

AppSec

Europe

May 2006 http://www.owasp.org/

Can (Automated) Testing Tools Really Find the OWASP Top 10?

Erwin GeirnaertPartner & Co-founder, ZION [email protected]+32478289466

2OWASP AppSec Europe 2006

Agenda

Introduction Testing Automated Tools OWASP Top 10


Introduction

In order to find vulnerabilities in web applications we need to identify them:Via code audit: a lot of workVia testing: manual or automated

Manual testing: a human being attacks a web application using his experience, knowledge and tools (open-source, self-made, IE )

Automated testing: a human being uses an automated vulnerability scanner to attack a web application


Existing studies

Arian Evans – Tools Taxonomy – OWASP 2005 Personal experience with tools Conclusion: still a lot of work

Dr. Holger Peine – Fraunhofer IESE Test of AppScan, Acunetix & WebInspect on WebGoat

and proprietary application Conclusion:

A lot of false positives A lot of false negatives Not one tool did what it should do: find the easy

vulnerabilities in WebGoat (they can’t read the lesson hints )

Reviews by Infoworld & eWeek


Testing

There is no standard to test web applicationsHow to test for vulnerabilitiesDifferent type of payloads that must be used

e.g. <script>alert(document.cookie)</script vs <body onload=alert(document.cookie)>

What should be the result of a test: how to detect a pop-up window in an HTML stream?

What should not be the result of a test: will a script tag embedded in another script tag really get executed?


Testing

OWASP Testing Guide is a framework and a guideline, not a technical step-by-step guide

OSSTMM - Open Source Security Testing Methodology Manual: more detailed but not on an web app level more on a network/OS level

No education or recognized certifications for security testing


Testing

People have different backgrounds:Network security: how experienced are they in

XML parsing, AJAX, SQL,…Functional testers: how do they know what a

security vulnerability is? How can they exploit a vulnerability?

Developers: hate to test or audit code Application security expert: has the experience

and the knowledge of the three groups above but are a rare species

Conclusion: Everyone has a different approach to testingAutomated tools also have a different approach


Automated Tools – Open-source

For free Run on multi-platforms, thank you Java No or very limited reporting Usage-mode: expert security tester Examples: Oedipus, Paros, Burp Intruder,

WebScarab Fuzzer, Spike, E-Or, …


Automated Tools - Commercial

Not cheap: license is application, server or network based

Very good reporting capabilities Run only on Windows Usage-mode: typical Next – Next clicking

usage but expert in application security and the tool is required for optimal results

Examples: Cenzic HailStorm, SPIDynamics WebInspect, Sanctum AppScan, Acunetix, NTOspider, …


OWASP Top Ten Most Critical Web Application Security Vulnerabilities

A1. Unvalidated Input A2. Broken Access Controls A3. Broken Authentication and Session

Management A4. Cross Site Scripting Flaws A5. Buffer Overflows A6. Injection Flaws A7. Improper Error Handling A8. Insecure Storage A9. Denial of Service A10. Insecure Configuration Management


Some questions

Is the Top 10 about vulnerabilities, attacks or bad coding practices?

How to differentiate the different classifications? Invalidated input (A1) is a vulnerability, XSS (A4)

is an attack against this vulnerabilitySame for A5, A6 and A7

How to define a test plan for the OWASP Top 10?

What are the payloads to discover the Top 10? Eg. 10000000 X or 10000000 A for buffer overflow?


A1. Unvalidated Input

Definition: Information from web requests is not validated before being used by a web application. Attackers can use these flaws to attack backend components through a web application.

Test: insert all possible values for parameters: GET, POST, hidden fields, cookies, HTTP Headers,...

Automated tools: do this very good, but lack classification of the errors returned


A1. Unvalidated Input

How to detect: examine result (and NOT error codes) and identify vulnerabilities SQL Injection: parse for SQL error codes :S No exception handling: parse for stacktraces? Authorization bypass: is that a Admin-button? Buffer overflow (Denial-of-Service?): empty HTML-page? LDAP Injection: different user attributes? ...

Ultimate test: exploit vulnerability MANUALLY -> THIS REQUIRES THE TESTER TO KNOW THE ATTACK PAYLOAD

What about non-English web applications?


A2. Broken Access Controls

Definition: Restrictions on what authenticated users are allowed to do are not properly enforced. Attackers can exploit these flaws to access other users' accounts, view sensitive files, or use unauthorized functions.

Test: login with valid accounts with different privileges and attempt to access protected parts like URLs, Struts actions, hidden fields,...

Automated tools: can guess known URIs like /admin but do this within the existing user context or as an anonymous user


A2. Broken Access Controls

What I want: expected output should be an authorization matrix: user A can access URI A, user B cannot access URI B, ... like a sitemap but with authorization levels


A3. Broken Authentication and Session Management

Definition: Account credentials and session tokens are not properly protected. Attackers that can compromise passwords, keys, session cookies, or other tokens can defeat authentication restrictions and assume other users' identities.

Test: analyse the authentication mechanism: is HTTPS used, secure cookie, random session-ID,...

Automated tools: do this out-of-the-box


A4. Cross Site Scripting Flaws

Definition: The web application can be used as a mechanism to transport an attack to an end user's browser. A successful attack can disclose the end user’s session token, attack the local machine or spoof content to fool the user.

Test: use RSnake’s cheat sheet for XSS filter evasion (http://ha.ckers.org/xss.html)

Automated tools: some tools inject a limited XSS pattern and for some tool you don’t know what they inject and you CAN’T change it. But if you have a web site with 1000 forms they are very useful to automate the injection. But ... If you find 1 XSS, you probably find more


A5. Buffer Overflows

Definition: Web application components in some languages that do not properly validate input can be crashed and, in some cases, used to take control of a process. These components can include CGI, libraries, drivers, and web application server components.

Test: replace every parameter with a lot of data: integers, strings, binary data,...

Automated tools: some tools inject a buffer-overflow patterns but with some tools you don’t know what they inject or you’re unable to change it. But if you have a web site with 1000 forms they are very useful to automate the injection

Results: crash of the web application, corrupt database, crash of the server so be very careful on a production environment

Automated tools: detect database corruption?


A6. Injection Flaws Definition: Web applications pass parameters when

they access external systems or the local operating system. If an attacker can embed malicious commands in these parameters, the external system may execute those commands on behalf of the web application.

Test: replace every parameter with command injection strings which depend on the operating system in use

Automated tools: some tools inject command injection patterns but with some tools you don’t know what they inject and it is impossible to change them. But if you have a web site with 1000 forms they are very useful to automate the injection

Results: output of the command injection must be obtained, how to automate this? E.g. Net user /add Erwin


A7. Improper Error Handling

Definition: Error conditions that occur during normal operation are not handled properly. If an attacker can cause errors to occur that the web application does not handle, they can gain detailed system information, deny service, cause security mechanisms to fail, or crash the server.

Test: corrupt parameters and look for propagating exceptions

Automated tools: by default Result: how to classify an uncaught

exception, this depends on the exception


A8. Insecure Storage

Definition: Web applications frequently use cryptographic functions to protect information and credentials. These functions and the code to integrate them have proven difficult to code properly, frequently resulting in weak protection.

Test: attempt to access configuration files via forceful browsing like web.xml, examine cookies and parameters, dump passwords from database via SQL Injection

Automated tools: are unable to exploit vulnerabilities in order to find passwords


A9. Denial of Service

Definition: Attackers can consume web application resources to a point where other legitimate users can no longer access or use the application. Attackers can also lock users out of their accounts or even cause the entire application to fail.

Test: attempt to brute-force accounts, performance test,…

Automated tools: have no problem to attack accounts and they don’t execute performance tests but when attacking a site with full force it can have some unexpected side-effects


A10. Insecure Configuration Management Definition: Having a strong server

configuration standard is critical to a secure web application. These servers have many configuration options that affect security and are not secure out of the box.

Test: use Google to retrieve vulnerabilities about SUT and try to exploit them

Automated tools: can test automatically for these vulnerabilities and when they have a built-in update function these are very useful


Conclusions

Automated Tools are not the silver-bullet to test for the OWASP Top 10

They can help a security tester to assess a web application faster

Security tester must master the tools and know the limitations

Combine open-source tools with commercial tools But automated tools will have difficulties with the

latest technologies: AJAX: asynchronous XML requests One-time tokens like in Struts, SAP BSP, … Thick clients e.g. Java Web Start Web services

owasp appsec europe 2006 automated tools

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