Questions tagged [cookies]

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 session, user's preferences, shopping cart contents, or anything else that can be accomplished through storing text data on the user's computer.

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20
votes
2answers
15k 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 ...
39
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1answer
7k 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 ...
39
votes
2answers
15k views

Will same-site cookies be sufficient protection against CSRF and XSS?

I must say, that I like this idea and it seems that it will bring a new form of protection against CSRF and XSS or at least it will reduce those attacks. So, how effective will this protection be? ...
121
votes
3answers
171k views

Session Authentication vs Token Authentication

I am trying to get a handle on some terms and mechanisms and find out how they relate to each other or how they overlap. Authenticating a theoretical web application and mobile application is the ...
18
votes
5answers
19k 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?
92
votes
4answers
70k views

Do I need CSRF token if I'm using Bearer JWT?

Context: Angular site is hosted on S3 behind CloudFront, separate from Express server that is used as API and almost all requests are XMLHttpRequests. All requests are sent without cookies (...
54
votes
1answer
39k views

Why use an authentication token instead of the username/password per request?

The author of https://stackoverflow.com/a/477578/14731 recommends: DO NOT STORE THE PERSISTENT LOGIN COOKIE (TOKEN) IN YOUR DATABASE, ONLY A HASH OF IT! [...] use strong salted hashing (bcrypt / ...
38
votes
4answers
24k 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 ...
17
votes
2answers
14k 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 ...
6
votes
5answers
24k views

Store username in cookie for a web site

I want to store the username for a web site in the coockie, is it secure? What an hacker can do with this info?
1
vote
3answers
13k 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 ...
42
votes
4answers
31k 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 bash:...
38
votes
6answers
29k 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 | ...
90
votes
5answers
19k views

How does Facebook track your browsing without third party cookies?

Facebook has served me an ad for a website I visited earlier in the day. I have third party cookies disabled and have not followed any links between the website and Facebook (links which could contain ...
50
votes
3answers
38k views

Why is it insecure to store the session ID in a cookie directly?

I am learning about session middleware. You have to supply a secret or the middleware complains: app.use(session({ secret: "abc", resave: false, saveUninitialized: false, store: new ...
51
votes
3answers
102k 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 ...
78
votes
7answers
41k views

Does a CSRF cookie need to be HttpOnly?

We recently were handed a security report containing the: Cookie(s) without HttpOnly flag set vulnerability, which we apparently had in one of our internal applications. The applied fix was as ...
3
votes
2answers
17k views

What is actually the purpose of encrypting the values in a cookie?

I was researching on internet security. When I reached at section Cookies, I happened to read that the values inside a cookie are generally stored only after encrypting them. But an encryption can be ...
8
votes
1answer
1k 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 ...
63
votes
5answers
118k 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 ...
22
votes
3answers
10k 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 ...
27
votes
5answers
14k 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 ...
14
votes
2answers
8k views

Why are cookies considered more secure against XSS?

This article discusses storing session tokens in a cookie vs in localStorage: https://stormpath.com/blog/where-to-store-your-jwts-cookies-vs-html5-web-storage/ The article states: Cookies, when ...
14
votes
5answers
10k views

CSRF protection with Session Id

To protect against CSRF, couldn't my page javascript just dynamically insert the session id from the cookie into the body of each HTTP request right before it's sent? The server would then just ...
16
votes
2answers
6k views

Is there a way to prevent hackers from using cookies to bypass two step verification?

Let's take Steam/Google/FB/Microsoft/Twitter logins as examples. All of them offer two step verification through SMS message. Let's say the hacker does not have access to my phone. But he has access ...
2
votes
1answer
5k views

Stopping Session Hijacking

If you noticed, I put "stopping" instead "preventing" in the title because I want my PHP application to be as secure as possible. I am wondering if anyone has any better ways to prevent session ...
34
votes
6answers
23k views

Can a secure cookie be set from an insecure HTTP connection? If so, why is it allowed?

With reference to some security paper I read, I found out that a cookie with the secure flag set can only be sent by the client over connections that are using HTTPS, not HTTP, but the cookie itself ...
10
votes
2answers
1k 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 ...
5
votes
1answer
5k views

What are HSTS Super Cookies?

A few questions : What are HSTS super cookie? How do they work? Why is possible to access them from multiple domains? Do I have to worry and if yes, how to mitigate their effect? Sources http://...
2
votes
1answer
675 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 ...
5
votes
1answer
2k views

Is session/cookie based authentication stateful or stateless?

Flask Web Development says The current login functionality implemented with the help of Flask-Login stores data in the user session, which Flask stores by default in a client-side cookie, so the ...
3
votes
3answers
913 views

Are flash cookies still a threat and that persistent?

One year (or more) ago flash cookies were really a problem, because they could not be deleted from within a browser. They were not managed by the browser but by the flash player. Flash cookies were ...
1
vote
3answers
635 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
1answer
234 views

How to prevent security risk when logout failed for authentication cookies

In the normal process, users request to logout from the client-side, then the server revokes that authentication cookie. Everything works fine if the network works as expected. But it seems that there ...
0
votes
1answer
1k views

should I not accept cookies for the sake of anonymity?

Let's say I had a Gmail account. Should I just not have a Gmail account, or should I not use their cookies? How bad are the cookies, in of themselves? I obviously wouldn't log into it, with my VPN or ...
0
votes
1answer
2k views

localStorage vs. HTTP-Only Cookies + XSRF: Is either better when it comes to XSS?

If I were to implement a common OpenID Connection pattern on a SPA, I might have the following relationship: Auth server <-----------> Client (browser) <-----------> App API server The ...
11
votes
5answers
5k 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 Mode"...
6
votes
1answer
3k views

Secure Flag and HSTS in HTTPS Only site

If I had a site only available in HTTPS should I still enable HSTS and Secure Flag?
5
votes
1answer
363 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, ...
3
votes
1answer
2k views

Signing (HMAC) cookie identifier

Related to this other question about sharing the secret to sign the cookies, my question is more trivial: how really secure is to sign a simple cookie identifier? In example, expressjs#session ...
3
votes
1answer
12k views

How to detect, inspect and delete a super cookie of a specific website? [closed]

Definition of supercookie from the paper I am reading: "Supercookies settle in parts of the system that are harder to erase, and include the usage of Flash Local Shared Objects and IE Local ...
2
votes
1answer
747 views

Doesn't Samesite cookie and Sameorigin policy effectively does the same job?

Pardon me if I am wrong, however, I am looking for an answer for my understanding that isn't the concerns regarding CSRF solved by both Samesite cookie and Same-Origin-Policy effectively? Then why is ...
0
votes
1answer
2k views

Import Wireshark Cookies into Firefox?

I'm trying to copy session cookies (collected using Wireshark) into a different Firefox sessions. But can't seem to find a method or working add-on to manage the cookies. Greasemonkey and ...
40
votes
4answers
78k views

Can a webpage read another page's cookies?

I was listening to Pandora as I logged in here, and the next commercial was about InfoSec. That set me wondering as to whether that was a coincidence (probably) or if they knew somehow. To make a long ...
29
votes
3answers
42k views

Store Auth-Token in Cookie or Header?

I do understand that a header is the "cleaner" solution to transport an auth-token from a trusted system to another in a REST call. But when you are in client-side JavaScript code, the world looks ...
32
votes
6answers
13k 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 ...
30
votes
6answers
18k views

Can't a user change his session information to impersonate others?

Can't an attacker just change his/her session (or cookie because it's stored locally) information then fool the server that he's the legitimate user? Say for example, if a website uses the database ...
24
votes
2answers
23k views

Is it safe to store a JWT in sessionStorage? [duplicate]

This article from Auth0 recommend storing the JWT locally in a local storage (or cookie). But this article from OWASP recommend not to story any sensitive data locally (not even sessionStorage) So, ...
22
votes
5answers
3k views

Good session practices

What are some good practices for ensuring logins, session IDs and session content are secure for a website?
48
votes
7answers
27k views

Why isn't stealing cookies enough to authenticate?

I tried to export all my cookies through the 'Edit This Cookie' extension on a logged-in page which uses cookie authentication. While logged out I tried inserting those cookies hoping that I would be ...