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EDIT

What one means by "a secure cookie" is ambiguous. To clarify:

  1. Secure as in sent over the https:// protocol — ie. cookie is not sent in plaintext. Known as the "secure flag"

  2. Secure as in the cookie cannot be read by Javascript running in the browser — ie. document.cookie will not work. Known as the "HttpOnly" flag.

This edit is to clarify that the original question is asking about the 2nd case.

Original Question

Is there any way to read a secure cookie with JavaScript?
I tried to do it using document.cookie and as far as I can see on this article about secure cookies and HttpOnly flag, I cannot access a secure cookie this way.

Can anyone suggest a workaround?

rmcsharry
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tzam
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    From [wiki](http://en.wikipedia.org/wiki/HTTP_cookie): A secure cookie is only used when a browser is visiting a server via HTTPS. – Pavel Hodek Nov 09 '11 at 11:39
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    @Pavel Hodek That's the wrong flag. The "secure" cookie flag has nothing to do with the HTTPOnly security flag. They have an awful naming system. – rook Nov 09 '11 at 18:28
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    The title of this questions ought to be changed to include the "HttpOnly" flag. As it stands it looks like the question is about the "Secure" flag. – Tom Nov 12 '18 at 14:18

3 Answers3

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Different Browsers enable different security measures when the HTTPOnly flag is set. For instance Opera and Safari do not prevent javascript from writing to the cookie. However, reading is always forbidden on the latest version of all major browsers.

But more importantly why do you want to read an HTTPOnly cookie? If you are a developer, just disable the flag and make sure you test your code for xss. I recommend that you avoid disabling this flag if at all possible. The HTTPOnly flag and "secure flag" (which forces the cookie to be sent over https) should always be set.

If you are an attacker, then you want to hijack a session. But there is an easy way to hijack a session despite the HTTPOnly flag. You can still ride on the session without knowing the session id. The MySpace Samy worm did just that. It used an XHR to read a CSRF token and then perform an authorized task. Therefore, the attacker could do almost anything that the logged user could do.

People have too much faith in the HTTPOnly flag, XSS can still be exploitable. You should setup barriers around sensitive features. Such as the change password filed should require the current password. An admin's ability to create a new account should require a captcha, which is a CSRF prevention technique that cannot be easily bypassed with an XHR.

Scott
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rook
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  • Could you please elaborate on the worm thing? That link doesn't work and didn't really understand much from the internet as well. Thank you. – Abhishek Jebaraj May 12 '17 at 13:22
  • @Abhishek Jebaraj If you don't understand the sammy worm, or CSRF tokens, then try first understanding the limits of the [same-origin policy](https://developer.mozilla.org/en-US/docs/Web/Security/Same-origin_policy) – rook May 12 '17 at 17:03
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    i want to get the expiry date of an http only cookie, how do I do that – PirateApp Oct 31 '20 at 15:56
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The whole point of HttpOnly cookies is that they can't be accessed by JavaScript.

The only way (except for exploiting browser bugs) for your script to read them is to have a cooperating script on the server that will read the cookie value and echo it back as part of the response content. But if you can and would do that, why use HttpOnly cookies in the first place?

Ilmari Karonen
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  • You might want to test it to know whether the user browser handles HttpOnly for cookies properly before allow the user to use your site from the particular browser. I'm looking for an example which can assure the browser support of HttpOnly flag. MS also advices to do so, but there is no further advice on the how: [Mitigating XSS with HttpOnly](https://msdn.microsoft.com/en-us/library/ms533046.aspx#httponly) – Ursegor Mar 18 '17 at 11:52
  • I found they advice browser version white listing. I might be wrong, but wouldn't it be a convenient way to check the support from javascript instead? Could you suggest any drawbaks on this? – Ursegor Mar 18 '17 at 12:02
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You can not. Httponly cookies' purpose is being inaccessible by script.

Akin Zeman
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    What is new or different in your answer than the already existing ones ??? – HDJEMAI Feb 18 '21 at 21:58
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    Same as the first sentence of previous answer: `The whole point of HttpOnly cookies is that they can't be accessed by JavaScript.` – HDJEMAI Feb 20 '21 at 08:27
  • @Akin Zeman: No need to use screaming caps. You may want to dive into Nonviolent Communication. – Gogowitsch Aug 03 '21 at 13:16