Looking for Vulnerable Code. Vlad Savitsky
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How to find vulnerable code in your Drupal project? Different attacks and how to protect your site? What to do if you find security problem in code/site?
Transcript of Looking for Vulnerable Code. Vlad Savitsky
Are you sure thatyour site is securesecure?
Site securitySite security
● Trusted, experienced and secure hosting
● Secure code● Security updates
Security UpdatesSecurity Updates
● Subscribe to Security-newshttp://lists.drupal.org/mailman/listinfo/security-news
● Use Drupal 7 core module Update Manager.
How secure is Drupal codeDrupal code?
Types of vulnerabilitiesTypes of vulnerabilities
Is Your Drupal-siteIs Your Drupal-siteCode Secure?Code Secure?
Speaker: Vlad SavitskySpeaker: Vlad Savitsky
Working at
Skype: vlad_savitsky
ICQ: 205535814
+38096 530 27 12
ChallengeChallenge
● http://google-gruyere.appspot.com/start● Gruyere / ru j r/ - a small, cheesy web ɡ ːˈ ɛə
application that allows its users to publish snippets of text and store assorted files.
● "Unfortunately," Gruyere has multiple security bugs ranging from cross-site scripting and cross-site request forgery, to information disclosure, denial of service, and remote code execution.
The goal is to discover bugs in Gruyere.
Cross-site scripting (XSS)Cross-site scripting (XSS)
● Allows attackers to inject script into Web pages viewed by other users.
● http://en.wikipedia.org/wiki/Cross-site_scripting
Handling Data Handling Data Golden RuleGolden Rule
● Store exactly what the user typed. ● When handling and outputting text in HTML,
you need to be careful that proper filtering or escaping is done.
UserDrupalCode
Database
ValidatedUser Input
User Input
Invalid Input
1. User sends some data1. User sends some data
2. Attacker sends code2. Attacker sends code
UserDrupalCode
Database
2. Not Well Validated
Input
1. InputJS
JS
3. User request a page3. User request a page
UserDrupalCode
Database
3. Not Well Escaped Data
1. Request
2. SQL-Query
JS
JS
4. User runs Attacker's code4. User runs Attacker's code
HTML page
Attacker'sJavaScript
Code
User
User
1. View page
Browser
2. Send data
Access BypassAccess Bypass
UserDrupalCode
2. Get Access
1. Request /devel/php
Cross-site request forgeryCross-site request forgery
● Ability to run some actions at server accessing some URL.
● Also known as a one-click attack or session riding and abbreviated as CSRF (pronounced sea-surf) or XSRF.
● http://en.wikipedia.org/wiki/Cross-site_request_forgery
User Profile
SaveSave
DeleteDelete
1. Find URL1. Find URL
http://example.com/user/10/deletehttp://example.com/user/10/delete
2. Post URL2. Post URL
HTML page
<img src=”URL” />
User
Admin
1. Post page
Server
3. Open URL
2. Send URL
Arbitrary code executionArbitrary code execution
● Ability to execute any commands of the attacker's choice on a target machine or in a target process.
● http://en.wikipedia.org/wiki/Arbitrary_code_execution
Session fixationSession fixation
● Session fixation attacks attempt to exploit the vulnerability of a system which allows one person to fixate (set) another person's session identifier (SID).
● Most session fixation attacks are web based, and most rely on session identifiers being accepted from URLs (query string) or POST data.
● http://en.wikipedia.org/wiki/Session_fixation
1. Send URL with SID1. Send URL with SID
User Admin
1. Send URL http://example.com/node/2?sid=123
DrupalCode
2. Login http://example.com/user/login?sid=123
2. Get Admin's session2. Get Admin's session
User3. Login as admin URL http://example.com/user/login?sid=123
DrupalCode
http://drupal.org/project/sharedsignonhttp://drupal.org/project/sharedsignon
How to find a vulnerability?How to find a vulnerability?
XSS high-risk zonesXSS high-risk zones
● theme().● t() and l().● dpm().● echo(). ● var_dump().● console.log().● watchdog().● drupal_set_message().
● Templates (.tpl.php).● Theme's code.● Preprocess functions.● $form_state values.● Validation messages
and default values.● Field type 'select' and
'options' attribute.● drupal_set_title().
<script>alert('xss');</script>
<img src=”notfound.png” onerror=”alert('xss');”>
watchdog('type','message <script type="text/javascript">alert("xss");</script>');
XSS TestXSS Test
How to find XSRF?How to find XSRF?
● Inspect hook_menu().● Inspect AJAX callbacks.● If secure tokens not used used then XSRF is
possible● See drupal_get_token().
Access bypassAccess bypass
● Check hook_permissions().● Search for permission names.● Check 'access_callback's in hook_menu().● Check if code works correctly with other
contributed modules and respects their access restrictions.
Code ExecutionCode Execution
● Search for 'eval', 'system' and etc.● Check code includes.● Check if files with code could be executed.● Search for php input format for blocks, nodes,
fields and etc.● Check if modules like devel, php and etc.
enabled.● Check if uploading files with php-code is
possible.
SQL injectionSQL injection
● Static queries.
Drupal Security TeamDrupal Security Team
Goals of the security teamGoals of the security team
● Resolve reported security issues.● Provide assistance for contributed module
maintainers in resolving security issues.● Provide documentation on how to write
secure code.● Provide documentation on securing your site.
How to reportHow to reporta security issuea security issue
● Do not post in the issue tracker or discuss it in IRC.● Mail to [email protected]● Provide as many details as you can. At least:
● Drupal version and/or module version.● Steps to reproduce the problem.
● Do not disclose the vulnerability to anyone before the advisory is issued.
● You will be credited in the security announcement.
How the security team How the security team works with issues?works with issues?
● Review the issue and evaluate the potential impact on all supported releases of Drupal.
● If it is indeed a valid problem, the security team is mobilized to eliminate it.
● New versions are created and tested.● New packages are created and uploaded to
Drupal.org.● When an issue has been fixed, use all available
communication channels to inform users of steps that must be taken to protect themselves.
Issues withIssues withcontributed modulescontributed modules
● The module maintainer is contacted with a deadline.
● When the maintainer fixes the problem, the security team issues an advisory.
● If the maintainer does not fix the problem within the deadline, an advisory is issued, recommending disabling the module and the project on Drupal.org is unpublished.
Additional ReadingAdditional Reading
● Core Security Advisories http://drupal.org/security
● Contributed Project Security Advisorieshttp://drupal.org/security/contrib
● The Drupal Security Team http://drupal.org/security-team
● Secure confguration of your Drupal sitehttp://drupal.org/security/secure-confguration
● Writing secure codehttp://drupal.org/writing-secure-code
● Cracking Drupal – The Drupal security bookhttp://crackingdrupal.com/
● This paper's website http://drupalsecurityreport.org
● OWASP Top Ten Projecthttp://www.owasp.org/index.php/Category:OWASP_Top_Ten_Project
Questions to speakerQuestions to speaker
Vlad Savitsky
http://shvetsgroup.com
Skype: vlad_savitsky
ICQ: 205535814
+38 096 530 27 12
