a cross site request forgery attack causes a visitor of a malicious website to send a request to a legit website to which he is already logged in including the session cookie.

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13
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4answers
4k views

How to protect against login CSRF?

http://seclab.stanford.edu/websec/csrf/csrf.pdf points out that most CSRF protection mechanisms fail to protect login forms. As http://stackoverflow.com/a/15350123/14731 explains: The ...
23
votes
5answers
16k views

What is the correct way to implement anti-CSRF form tokens?

I am fully aware of CSRF and have already implemented some safe forms, but I have never been happy with the results yet. I've created tokens as a md5 of username, form info and a salt and stored it ...
31
votes
7answers
14k views

Why refresh CSRF token per form request?

In many tutorials and guides I see that an CSRF token should be refreshed per request, my question is why do I have to do this? Isn't a single CSRF token per session much easier than regenerating one ...
17
votes
4answers
14k views

CSRF protection with custom headers (and without validating token)

For a REST-api it seems that it is sufficient to check the presence of a custom header to protect against CSRF attacks, e.g. client sends "X-Requested-By: whatever" and the server checks the ...
4
votes
1answer
439 views

Why CSRF's JS cant read token by GETting html

1) User is logged in bank.com in one tab, where everything is secured by CSRF tokens. Then he opens evil.com in another tab. 2) Javascript in evil.com might try to make a POST request to ...
23
votes
2answers
46k views

Why is the Access-Control-Allow-Origin header necessary?

I understand the purpose of the Access-Control-Allow-Credentials header, but can't see what problem the Access-Control-Allow-Origin header solves. More precisely, it's easy to see how, if ...
4
votes
2answers
2k views

Double Submit Cookies vulnerabilities

Is the Double Submit Cookies mechanism vulnerable anything other than XSS and sub-domain attacks? All CSRF protection mechanisms are vulnerable to XSS, so that's nothing new. I'm just wondering if I ...
3
votes
4answers
1k views

Can a CSRF CAPTCHA be defeated?

One defense that developers use to protect against a CSRF attack is to implement a CAPTCHA in critical steps. A CAPTCHA ensures that a human is at the keyboard approving the activity. But I've ...
44
votes
2answers
14k views

When the use of a AntiForgeryToken is not required /needed?

I'm running a rather large site with thousands of visits every day, and a rather large userbase. Since I started migrating to MVC 3, I've been putting the AntiForgeryToken in a number of forms, that ...
28
votes
1answer
8k views

Is Django's built-in security enough?

I have learned that Django provides built-in protection against the three main types of web app attacks (SQL injection, XSS and CSRF), which is really awesome. Yet I have spoken to a few Django ...
13
votes
2answers
4k views

How to do Ajax securely?

This question is inspired by this security question http://security.stackexchange.com/questions/1707 What are the threats in using Ajax? (Please note I am talking about security threats, not ...
10
votes
2answers
9k views

Does ASP.NET Viewstate implicitly prevent CSRF attacks? What does this mean for MVC?

If an encrypted ASP.NET Viewstate is submitted with every form, and control POST, does that mean that ASP.NET is less vulnerable to CSRF than other solutions with this? What is the extent and ...
7
votes
2answers
5k views

What is the purpose of OAuth 2.0 redirect_uri checking?

The OAuth 2.0 specification's authorization code mechanism includes redirect URI checking from the site you redirect to. See steps D and E in section 4.1 of the spec. Also, section 4.1.3 describes in ...
2
votes
2answers
379 views

Protecting websites from outdated browsers and plugins via a whitelist/blacklist combination?

Aside from using browser headers, I want to blacklist/whitelist browser and plugins from my site so that I can prevent these older unpatched systems from (1) being a general user of my site (2) ...
3
votes
1answer
384 views

Preventing CSRF attacks against WebSocket communications

I have read the thread about CSRF attacks in websockets (Do websocket-powered web apps (e.g. "comet" apps) have to worry about CSRF?) and also some more material regarding websocket ...
3
votes
2answers
551 views

Do WebSocket-powered web apps (e.g. “comet” apps) have to worry about CSRF?

The standard advice for HTTP applications wanting to prevent Cross Site Request Forgery is to include a random token on each state-changing request (usually POST) which is verified by the server ...
1
vote
1answer
172 views

CSRF protection for unauthenticated requests, actions, searches or comments?

I have gone through the example of CSRF funds transfer from a bank where the user is logged in. Similarly I have looked at CSRF in case of email updating. I think I understood it but I am not quite ...
0
votes
1answer
167 views

CSRF on GWT apps : bypassing the Same-Origin policy

At work we suspect a GWT app (that is not in production yet) we own to be vulnerable to CSRF. We have to look at it from a black-box point of view before a third-party security audit will be ...
15
votes
3answers
5k views

What risks do Cookieless sessions have? What are the mitigations?

I'm debating if I should support cookieless sessions in my web app. It would look something like this: http://www.example.com/(S(lit3py55t21z5v55vlm25s55))/orderform.aspx Since the URL is never ...
5
votes
1answer
5k views

How does a CSRF token prevent an attack, and how can I safely use/avoid it for my JSON API?

I'm trying to make an iOS app communicate with a Ruby on Rails website using JSON. While trying to post a login to create a user session, I discovered I was missing a CSRF token. I had no idea what ...
16
votes
3answers
872 views

Why CSRF Token has to be a Cryptographically Strong Random number, in Double Submit Cookies method?

I was just going through the OWASP's Cheat Sheet for CSRF Prevention. In the Double Submit Cookies method, I saw this the site should generate a (cryptographically strong) pseudorandom value ...
12
votes
2answers
8k views

CSRF With JSON POST

I am playing around with a test application which accepts JSON requests and response is also JSON. I am trying to do a CSRF for a transaction which accepts only JSON data with POST method in request. ...
8
votes
4answers
1k views

Can anti-CSRF token prevent bruteforce attack?

I am not much experienced with brute force attacks but I was wondering Suppose, you have a website www.example.com and you want to do brute force attack on that login form but that login form is ...
6
votes
7answers
1k views

Should I prevent sending of GET requests for urls that are normally operated with POST request?

There is an url that is normally operated using POST requests (i.e. POST request is sent when user submits form). But attacker can form GET request with parameters that are sent in POST request. This ...
5
votes
4answers
13k views

Security issues using iframes

We are looking to move to iframes due to technical challenges. By moving to iframes it will be easier to manage the technical issues. But we are not totally sure of security implications of iframes. ...
4
votes
1answer
911 views

How to prevent CSRF if you want to include Flash plugins in your form like Uploadify in your form?

What is CSRF? I need a basic definition that is not just lifted from Wikipedia. I understand SQL injection, XSS, cookie poisoning, but I just cannot wrap my mind around this. I am using a ...
9
votes
1answer
589 views

Why can't you steal the synchroniser token to do CSRF? [duplicate]

I'm reading up on CSRF and I came across synchroniser tokens. I don't understand why you can't do a CSRF to get the token to do a real CSRF. Example: bank.com has a form like this at ...
5
votes
2answers
642 views

Why are CSRF tokens used so often?

CSRF tokens are used a lot. The server sets a token in cookie for that domain that either (1) include in the HTML form or (2) Javascript can read and include in the request. The server verifies the ...
5
votes
3answers
476 views

Are CSRF Attacks Really Blind

I'm new to CSRF attacks but don't see how they are always blind. Let's say we are dealing with a site where the asset we need to protect is the HTTP response. Something like one's medical history. ...
4
votes
1answer
848 views

Does returning `Access-Control-Allow-Origin: *` weaken the security of JSON GET responses?

The W3C CORS recommendation states: Certain types of resources should not attempt to specify particular authorized origins, but instead either deny or allow all origins. ... 3. A GET ...
3
votes
2answers
267 views

What's a good time period before refreshing CSRF token of the user session?

I am using a form token to prevent CSRF attacks. Those tokens are stored and tied to a user's session. Now I want to refresh the token only every N minutes or hours so that the user's don't experience ...
3
votes
3answers
209 views

Why doesn't XSS vulnerability from the site launching the CSRF attack make the Synchronizer Token Pattern insecure?

I was reading this question about using Synchronizer Token Pattern to protect against CSRF and the comments of the answer intrigued me. Of course, as the last comment says, if your site has an XSS ...
1
vote
2answers
2k views

Should CSRF 'Double Submit Cookie' technique have a different seed value for the cookie versus the HTTP POST?

I'm reading about the OWASP double submit cookies method of protection and there it states that the cookie value between the header and form should match. That seems to be somewhat of a risk, as the ...
5
votes
2answers
1k views

Ajax and CSRF protection

Without going into too much details I have a site which is 100% Ajax. All requests to the site (both GET and POST) are done via Ajax. Now I have to implement CSRF protection, and all the solutions I ...
4
votes
1answer
769 views

Is one CSRF token per session is adequate with HTTPS?

Ours is a Ajax heavy application with concurrent Ajax requests. Generating unique tokens with each request or expire and creation of new tokens after a certain interval could get tricky with multiple ...
3
votes
3answers
166 views

Why is the synchronizer token pattern preferred over the origin header check to prevent CSRF

I am well aware of the concept of CSRF, and I think I am also aware of the possible protection possibilities, as described by OWASP. However, I'm not sure why the synchronizer pattern seems to be ...
3
votes
2answers
797 views

Why does Double Submit Cookies require a separate cookie?

According to https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)_Prevention_Cheat_Sheet#Double_Submit_Cookies: When a user authenticates to a site, the site should generate a ...
2
votes
2answers
4k views

How does ViewState protect against CSRF?

According to the OWASP CSRF Cheat Sheet viewStateUserKey for ASP.NET ViewState is acceptable to prevent csrf attacks, but I really don't get how. I get that this makes it hard for an attacker to ...
1
vote
1answer
405 views

How to bypass XMLHttpRequest header protection for a CSRF attack

A client is only submitting forms using XMLHttpRequest with the use of a header (X-Header: [any value would be correct]) to protect against Cross Site Request Forgery attacks. I know this is not the ...
1
vote
1answer
2k views

CSRF with OAuth or Bearer Authorization headers

I am designing a RESTful API which is to be accessible from a web browser. The API is protected by Basic authentication. I understand the concept of CSRF, and the mitigations proposed (I found both ...
0
votes
1answer
112 views

OAuth + Confused Deputy + access token verification + state parameter

Google's "Using OAuth 2.0 for Client-side Application" article at https://developers.google.com/accounts/docs/OAuth2UserAgent states that the client MUST validate all access tokens to verify that it ...