Fix me if you can - DrupalCon prague

We prepared you a site to ﬁx.
It has been broken in many, many places.
You will work in teams to ﬁx it.

About the session

We are drupalists, consultants, working in the
Acquia Professional Services team

Alex Ku
Balázs Dianiska
Hernâni Borges de Freitas
Théodore Biadala
About us

Alex
drupal.org: alexku
linkedin: Alex Ku

Balázs
drupal.org: snufkin
twitter: @thesnufkin

Hernâni
drupal.org: hernani
twitter: @hernanibf

drupal.org: nod_
twitter: @nod_
Théodore

LAMP stack
Varnish is installed and set up
We set up a site for each team
Each site is broken in many ways
What is in the box

15:45 - 16:00 - Introduction and setup
16:00 - 16:25 - Site building
16:25 - 16:35 - Break
16:35 - 17:00 - Security
17:00 - 17:10 - Break
17:10 - 17:35 - Performance
17:35 - 18:00 - Wrap up and questions
Lab schedule
http://fixme.acquia-ps.com

What we prepared:
1 site per team
1 login per site
We can create 25 sites, so lets split into teams

Address: http://fixme.acquia-ps.com
Password will be on the site
Setup

Site building
•  Best practices
§  Drupal coding standards
§  Security
§  Performance
•  Code architecture
•  Content architecture
•  Conﬁguration

Review process
1.  Make the site run
2.  Run automated tools
3.  Triage the output
4.  Read all the custom code*
5.  Dig into messy areas

Tools
•  Update
•  Hacked
•  Coder
•  PHP_CodeSniﬀer
•  Insight
•  A Brain

Red flags
•  PHP Filter module
•  PHP in templates
•  Many, many template ﬁles
•  Many views/blocks/panels with a similar
name
•  Many content types with one or two nodes


Exercise 1- Code hacked
•  Looking for hacked core / contrib
•  Go to hacked report and run it

Exercise 2- Missing updates
•  Run Update module
•  Explain how to keep it up to date


Exercise 3 - Coding standards
•  Coder & PHP Code Sniffer
•  Find jquery_countdown and email_login_link

Exercise 4 - Views architecture
•  Check “News” views

Exercise 5 - Content architecture
- article => 1320
- teaser => 805
- microsite => 273
- …
- sports_homepage => 1
- teams_homepage => 1
- change_password => 1
- login_form => 1
- footer_homepage => 1


Secure your
Drupal site by first
hacking into it

Drupal vulnerabilities by popularity
reported in core and contrib SAs from 6/1/2005 through
3/24/2010

Access Bypass
http://www.flickr.com/photos/nikonvscanon/
1816459664/

Access Bypass
“Inadequate or weak access control over
a resource”
Authentication
Authorization

Access Bypass
When a user can
see something they shouldn’t
perform an action they shouldn’t

Stop Access Bypass
Implement checks
before providing an action
after undertaking an action

Access Bypass Hands-on
First as anonymous user goto:
http://fixme.acquia-ps.com/[teamN]/admin/dashboard/users/all
What’s there:
VBO allows sending an email to any address and blocking
users
How can we fix this?

Access Bypass Hands-on
The problem is in:
●  “Bypass views access control” permission
●  “Actions permissions (VBO)” module

http://www.flickr.com/photos/nathaninsandiego/3757033518/ http://flic.kr/p/6HZMaY
Cross Site Scripting

Cross Site Scripting
XSS
Javascript
Performing actions without your intent
Everything you can do XSS can do faster

Stored XSS Step 1
DrupalAttacker
Reques
t
J
S
DB
J
S

Stored XSS Step 2
DrupalVictim
Reques
t
Respons
e
J
S
J
S
DB

Stored XSS Step 3
DrupalVictim
Reques
t
J
S
DB
J
S

$node = node_load($nid);
$title = $node->title;
drupal_set_title($title);
...
(later, in page.tpl.php)
...
<h1><?php print $title; ?></h1>

XSS Hands-on
First as admin user go to:
http://fixme.acquia-ps.com/[teamN]/user/1 and
notice value for Full Name
Then open this page:
http://fixme.acquia-ps.com/[teamN]/node/56
Now open the first page again and notice the Full
Name has changed
How can we fix this?

XSS Hands-on
The problem is in:
●  Filtered HTML text format allowing <script> tag
●  Security Review module helps detecting issues like
this

http://www.flickr.com/photos/jackofspades/4500411648/
Cross Site
Request Forgery

Cross Site Request
Forgery
CSRF
Taking action without confirming user
intent

Cross Site Request
Forgery
Attacker makes action occur on your
behalf
Using your session
Without you knowing or approving

Cross Site Request
Forgery
/comment/reply/1
Attacker
img
src=delete/1
Drupal

Cross Site Request
Forgery
Victim html
cookie
Drupal
Drupal
/user/login

Cross Site Request
Forgery
Victim DrupalDrupal
/node/1

Cross Site Request
Forgery
Victim html DrupalDrupal
/node/1
/delete/1

validate intent
“Did the user mean to carry-out
action”
or
“Could an attacker execute this on
behalf of a user”
Protecting against CSRF

Something secret, unique to the
action
Shared between trusted user and
server
Validate intent?

only if using Form API
generates form token
checks token when processing form
Drupal protects against
CSRF with Form API

fancy AJAX, GET callbacks
drupal_get_token()
drupal_valid_token()
Generate your own token

attacker identifies weak point
gets authorized account to take action
protect by confirming intent
Cross Site Request Forgery

As anonymous user add a comment with an image like
this:
<img src=”admin/content/unpublish/[nid]”>
Visit the page with the comment as admin
Check if the node is unpublished
How can we fix this?
CSRF Hands-on

A proper fix would require adding protection in callback
function for path: admin/content/unpublish/[nid]
A quick fix would filter img tags in Filtered HTML
CSRF Hands-on

SQL Injection
Mixing data received from the user with
database query allows an attacker to perform
custom actions against the database

As anonymous user go to:
http://fixme.acquia-ps.com/show/node?nid=[nid]
You should see a title and status of a single node
Now append this to the url:
“ union select uid, name, status from users”
You should see names of all users
How can we detect and fix this?
SQL Injection Hands-on

Security Review module helps detect
simple SQL injection vulnerabilities

Fixing this would require rewriting custom code

The vulnerable lines are:
$nid = $_GET['nid'];
$r = db_query("SELECT nid, title, status FROM
{node} WHERE status = 1 AND nid = $nid");

The ﬁx would look something like:
$nid = $_GET['nid'];
$r = db_query("SELECT nid, title, status FROM
{node} WHERE status = 1 AND nid = :nid",
array(“:nid” => $nid));


Automation
http://www.flickr.com/photos/hubmedia/2141860216/

Steps to a mostly automated
reviewSecurity Review: drupal.org/project/security_review
Hacked: drupal.org/project/hacked
Coder: drupal.org/project/coder
Secure Code Review
drupal.org/project/secure_code_review
Vuln: github.com/unn/vuln
HTML Purifier:
drupal.org/project/htmlpurifier
More: http://drupalscout.com/node/11

Performance

Slow? What you mean?
•  Backend slowness
•  Services that website use are slow
or unresponsive (dbs)
•  Application too complex
•  Server resources overload
•  Frontend slowness
•  Too many assets
•  Slow connection between browser
and server.
•  JS slowing the DOM (re)rendering

Profile
Look for pages you suspect
•  Start by easy ones
•  404 page (the fastest page you
can get).
•  Node view page
•  Homepage
•  Continue with the ones your data
marked as slow.
Time for some research

Benchmarks
Ideally your normal pages should
take
•  1 ~ 1.5 sec
•  40 ~ 60 mb of memory
•  100~300 queries per page
Simpler pages like 404 are good
indicators of what is the fastest all
other pages will run.

Profiling tools
Chasing it
•  Use Devel module (
http://drupal.org/project/devel ) to
have a fast indication of page load
times and memory consumption.
•  Use XhProf Module to profile the
page and understand slower
components.
•  Use timer_start(), timer_read()
functions in situations where you are
unsure.

Typical #1 – Slow queries
•  First look to profiling data shows something really slow.
Problem
•  Related to the database (Wall time vs Total Time).
•  Number of queries is low, so probably it’s a single query.
Solution
•  Reduce query time in views ; Use Views Lite Pager
Devel XhPro
f

Problem
•  High number of queries
•  High memory consumption
•  High number of function calls
•  All those little queries and memory consumption mean that
you are loading lots of information from the database.
Solution
•  Look to XhProf and identify the root cause of all the excessive
function calls.
Devel XhPro
f
Typical #2 – Extra complexity

Typical #3 – Edge cases
•  Slow functions only detectable by XhProf
• Eg: When problem is in PHP execution
• Problematic if using popular hooks (hook_init,
hook_node_load).
•  Infrastructure not being properly used
•  Requests bypassing Varnish
•  Not enough APC memory
•  Blocks rendered in all pages and content hidden at template
level.
•  Theme_rebuild and cache_clear_all in middle of code.

Typical #4 – Special tasks
•  Usually a task executed in special situations or in
certain pages that seriously slows down the platform.
•  Synchronizations of thousand of nodes from web
services.
•  Synchronization of all user base from LDAP.
•  Sending thousand of mails via Cron.
•  Even worst when those tasks are called by normal
page views.

Hands On Time

1.  Enable Devel
> Admin / Config / Devel -> Display query log, Display
page timer, Display memory usage
1.  Enable XhProf
> Admin / Config / XHProf
1.  Enable a browser inspector tool (Google Chrome
Developer tools or Firebug or etc..)
Exercise 1 - Enable tools

1.  Go to Drupalistas tab
2.  Click on Demo user and Drupal commits
Exercise 2 - Slow Query

1.  Go to Drupalistas tab
2.  Click on Demo user and Drupal commits
3.  Look to devel query log.
4.  Go to user / uid 1 and see the difference
Exercise 2 - Slow Query

1.  Go to a 404 page ( /prague)
2.  Look to XhProf report
Exercise 3 - Missed blocks

3.  Find the missing blocks (weather)
4.  FIx it by giving the right path

3.  Find the missing blocks (weather)
4.  Fix it by giving the right path

- Go to the sessions tab.
- Look to XhProf and Devel.
- Look to amount of memory and CPU.
Exercise 4 - Complexity

- Go to the sessions page.
- Look to XhProf and Devel.
- Look to amount of memory and CPU.
- Look to code to understand the amount of node_loads.
- Disable custom block and enable views block.
- Enable block cache alter
- Check difference
Exercise 4 - Complexity

- Go to a Drupalcon node
- Refresh a few times the page. Look to headers.
- Look to all requests done by the page.
Exercise 5 - Problems in
infrastructure

- Go to a Drupalcon node
- Refresh a few times the page. Look to headers.
- Look to all requests done by the page.
- Identify missing header in the ajax Call done to get
attendance
- Look to code
Exercise 5 - Problems in
infrastructure

1.  Reduce complexity. Make sure your site is as slim as possible.
2.  Cache where you can. At all levels.
3.  Maintain cache as long as possible as long it is acceptable.
4.  Compute behind the scenes when you can.
5.  Distribute the heavier tasks to larger intervals.
6.  Grow infrastructure if you are reaching server limits.
After you identified the
problems
Caching after optimizing

Performance
Can it be cached? Cache it!
•  Page caching, block caching, panels caching, views
caching, caching API..
•  Review caching strategy:
•  https://www.acquia.com/blog/when-and-how-caching-
can-save-your-site-part-2-authenticated-users
•  Guarantee that caching is effectively helping you.
•  Don’t clear it too often.
•  Not used only by a minority.

Summary
●  Make sure to look for others suffering from the same
problem.
●  Never hesitate to ask the most basic questions.
●  Go step by step, exclude possibilities if uncertain.
●  Learn the tools we introduced you to.
●  Always try to understand the whole system, not just the
part throwing the error.

So, before your questions.
I do have a question.
Would you like to join Acquia?
We are hiring EVERYWHERE in Europe!
• Consultants
• Support
• Sales
• Engineering

Thank you for your attention. Now question time!

THANK YOU!
WHAT DID YOU THINK?
Locate this session at the
DrupalCon Prague website:
http://prague2013.drupal.org/schedule
Click the “Take the survey” link

Fix me if you can - DrupalCon prague

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