A cookie, also known as an HTTP cookie, web cookie, or browser cookie, is used for an origin website to send state information to a user's browser and for the browser to return the state information to the origin site. The state information can be used for authentication, identification of a user ...

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25
votes
1answer
3k views

What cookie attacks are possible between computers in related DNS domains (*.example.com)?

Here, several servers in the same DNS domain emit cookies under a variety of settings (scope, HTTPS, Secure) and another host emits a cookie with the same value. Example Suppose a user has the ...
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 ...
30
votes
4answers
17k views

Demystifying Web Authentication (Stateless Session Cookies)

I'm currently researching user authentication protocols for a website I'm developing. I would like to create an authentication cookie so users can stay logged in between pages. Here is my first ...
10
votes
2answers
6k views

Is it safe to store the password hash in a cookie and use it for “remember-me” login?

I want to store an encrypted string of the password hash in a cookie and use the hash to lookup the user and log them in (if they want to be remembered). Is this safe? The password is one-way hashed ...
28
votes
2answers
27k views

How can I check that my cookies are only sent over encrypted https and not http?

I read a blog post GitHub moves to SSL, but remains Firesheepable that claimed that cookies can be sent unencrypted over http even if the site is only using https. They write that a cookie should be ...
9
votes
5answers
3k views

Does setting httponly prevent stealing a session using XSS?

If a session token is stored in a cookie that has httponly set, is there any way that a XSS vulnerability could allow a malicious user to steal a users session token?
10
votes
2answers
783 views

When are HTTP session cookies at risk over Wi-Fi?

If I'm using websites that do not use HTTPS, but I'm on a WEP-protected Wi-Fi network, are my cookies safe from being sniffed by third-parties? Are cookies only at risk during login, or am I at risk ...
12
votes
3answers
3k views

Protecting against cross-subdomain cookie attacks

I have been reading about cross-subdomain cookie attacks here. A quick overview of how it works (from Wikipedia): A web site www.example.com hands out subdomains to untrusted third parties One such ...
8
votes
5answers
3k views

What do the various browser “private modes” do?

Recently there has been some disagreement as to what "private mode" means when it comes to various browsers. Primarily I am referring to... IE's "InPrivate Browsing" Google Chrome's "Incognito ...
5
votes
1answer
256 views

What issues might exist with TLS-OBC's emulation of Browser Certificates?

TLS-OBC is an RFC proposal that increases SSL/TLS security by using certificates on both ends of the TLS connection. What's special here is that the client is permitted to dynamically create a local, ...
4
votes
6answers
3k views

Is cookie-based XSS exploitable?

Today I've found interesting site that output your cookie value directly to the page, so if I modify the cookie value I can XSS myself. e.g <span id=statistics>Last visit: ...
3
votes
4answers
3k views

Can a session be hijacked if the user is redirected from HTTPS to HTTP after login?

I am developing a web app, which makes HTTP calls as long as the user is not logged in. Once the user clicks the login button, he is sent to a "login page" that is HTTPS. The login makes an Ajax call ...
3
votes
1answer
253 views

What servers or clients are immune to related-domain cookie attacks? (*.example.com)

In this question, I want to identify browsers, servers, or implementations that are immune from related domain cookie attacks (e.g. a.example.com vs b.example.com). Lacking any tangible solution, ...
22
votes
6answers
11k views

Secure Session Cookies

While looking up methods for creating secure session cookies I came across this publication: A Secure Cookie Protocol. It proposes the following formula for a session cookie: cookie = user | ...
30
votes
4answers
40k views

Why is passing the session id as url parameter insecure?

I recently followed a discussion, where one person was stating that passing the session id as url parameter is insecure and that cookies should be used instead. The other person said the opposite and ...
19
votes
5answers
2k views

Good session practices

What are some good practices for ensuring logins, session IDs and session content are secure for a website?
12
votes
4answers
7k views

avoid hitting DB to authenticate a user on EVERY request in stateless web app architecture?

Summary Once a user logs into a web site and his username/password credentials are verified and an active session is established, is it possible to avoid hitting the DB for each and every request ...
24
votes
6answers
6k views

How can I prevent tracking by ETAGs?

An ETAG is a HTTP header that is sent-behind-the-scenes between a web browser and an web server. This value is intended to control how long a particular file is cached on the client side. There is ...
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 ...
7
votes
3answers
2k views

Is my session-less authentication system secure?

So, I've created an authentication system. Poured over it for any kind of security flaws and tested the crap out of it. I think it's fairly secure, but there is one "different" by-design aspect of it ...
3
votes
2answers
1k views

Is my current method of handling session cookies insecure?

I'm writing a multi-tenant application where accounts are scoped by subdomains. This adds considerable complexity and I'm starting to worry about security. Each user can have several accounts. For ...
6
votes
3answers
1k views

What authentication system (OpenID, Facebook, etc) permits Javascript-free and/or Cookie-Free operation?

I'm looking for an authentication system that relies on 3rd parties (ADFS, OpenID, SAML) but doesn't rely on cookies or Javascript... or at least can make them optional. My intent is to gracefully ...
5
votes
3answers
660 views

Are there security (esp. privacy) benefits to deleting cookies?

As the title says, I'm wondering if there are any security/privacy benefits to managing cookies - that is, managing by deleting cookies you don't want or need. I deleted all my cookies about a week ...
4
votes
1answer
853 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 ...
4
votes
3answers
1k views

Session fixation attack

Given the following conditions, Session ID does not change upon login Session ID travels in form of HTTP cookie There is no cross site scripting/redirection vulnerability on the login page is it ...
3
votes
2answers
226 views

Stealing document.cookie from Google domain, is this a privacy breach?

When I am logged into the Google and prints document.cookie I could see following cookies. My doubt is what all an attacker can do if attacker could steal these cookies of the victim using exploiting ...
3
votes
1answer
1k views

Signing session cookies

The Play Framework for Scala has support for signed session cookies. In the application configuration file is an "application secret" that is set as a secure random number when the application source ...
1
vote
1answer
75 views

What's the advantage in allowing 3rd party cookies?

I understand why people want to block 3rd party cookies - I would like to know though what would I be missing out from blocking them? Why do browsers like Chrome have them on by default? Is it simply ...
0
votes
1answer
417 views

Which approach to encrypting data on a per-user basis is more secure?

As a bit of a thought experiment, I've been thinking through how one might design a web application where a user's data (say, from a form on a webpage) is stored, encrypted, on the server, using a ...
8
votes
1answer
535 views

Identifying, analyzing, and predicting weak session cookies

To elaborate on this, I'm looking at this from the perspective of a hacker/penetration tester. Many times I have seen web applications that I know have weak cookies. I can tell this because I can ...
3
votes
4answers
226 views

Improving the privacy of a casual Web user

I am interested in improving the privacy available to me as a casual internet user with a default browser. I think that Tor is too slow and that the "Privacy Mode" in browsers isn't really practical. ...
2
votes
2answers
390 views

Can sessions be handled securely with cookies disabled?

I've been doing some reading here about session ID handling, and have learned that it's generally a bad idea to include a session ID in the HTML source code, and/or on the query string. For example Is ...
1
vote
1answer
92 views

How do banks determine when to ask for two factor authentication?

I was playing around with trying to figure out how my bank knows when to give me a two factor authentication prompt. I had originally thought it was based on my cookies and maybe my IP address. But ...
1
vote
3answers
156 views

Can websites tell whether that I am visiting them using the same device?

Assuming that I am browsing a website ( say: Amazon.com) using Private/Incognito mode, and I clear my cookies, and have VPN turn on. Will the website still be able to identify that my device has been ...
1
vote
3answers
475 views

Is this approach of securing cookie secure?

I could not find writeups about secure cookies so I have done some thinking. (I already have a "secure" password database with bcrypt and salt) Steps: User logs in Save user IP + randomstring in ...
1
vote
2answers
280 views

Is it okay from a security perspective to read foreign (untrusted) cookies in a trusted network?

From a security point of view, is it okay to read foreign (untrusted) cookies (from 3rd parties on the Internet) on your internal (trusted) network, or should you only read them within the DMZ areas ...