Na Bugtraq pojawiła się prezentowana przez nas poniżej informacja o błędach w Mozilli starszej niż 0.9.7 oraz Netscape w wersji 6.1. Dzięki nim można wyciągnąć z przeglądarki zawartość prawie dowolnego ciasteczka, czego przykład można obejrzeć tutaj.
Żeby się zabezpieczyć, wystarczy zaktualizować swoją przeglądarkę lub po prostu zwracać uwagę na URLe typu http://alive.znep.com%00www.passport.com/cgi-bin/cookies.

  From: Marc Slemko   To: bugtraq@securityfocus.com  Subject: Mozilla Cookie Exploit    A while ago I discovered a bug in Mozilla that lets you steal cookies for  any domain by convincing the browser to load a specially formatted URL; I  have been too busy to get around to making the details known earlier, so  here they are.  This is similar to holes that have been found, both by  myself and by others, previous in IE.  Details available at  http://alive.znep.com/~marcs/security/mozillacookie/ and are also included  below.  Update to Netscape 6.2.1 or Mozilla 0.9.7 for a fix.  Using open  source products doesn't magically make you invulnerable to security  problems like those that plague Microsoft.                                 Mozilla Cookie Exploit                          Marc Slemko                   Last Modified: $Date: 2002/01/22 05:06:04 $                                $Revision: 1.6 $                                          Table of Contents       [1]Executive Summary     [2]What's New     [3]Background     [4]Details     [5]Example Exploit       Executive Summary       Cookies are often used to identify and authenticate users to a     website. If an attacker can steal a user's cookies, then they can     impersonate that user. The completeness of the impersonation and the     actions the attacker can perform as that user depend on how the     particular site uses the cookies.          This bug in Mozilla allows an attacker to, if he can convince the     user's browser to load a given URL, steal their cookies for any given     domain. It does not require that active scripting is enabled in the     browser, and can be done with something as simple as an image tag,     allowing for hassle free use in HTML email, web based email services,     etc.          As expected, this bug is also present in Netscape 6.1. Upgrade to     Netscape 6.2.1 or Mozilla 0.9.7 or higher, which fix this bug.          The take-away message is that, due to implementation bugs in browser     and in web applications, cookies can be stolen. It is critical that     any application that depends on cookies does so with an understanding     of this fact, and takes appropriate measures to limit the damage that     can be done using stolen cookies.       What's New         * Current Status Summary: (last updated Mon Jan 21 20:48:17 PST         2002) I finally got around to making this vulnerability public.       * mid-Jan 2002: Netscape put up a [6]note on their site saying that         there was a security hole that they fixed.       * Sometime between when I reported this bug to Netscape and when I         made it public: This bug was fixed with the release of Netscape         6.2.1 and Mozilla 0.9.7.       * November 15, 2001: I reported this bug to Netscape via their         security bug submission form. I had trouble finding a documented         method for submitting security bugs to mozilla.org, but eventually         figured out that security@mozilla.org existed. In any case, both         submissions found their way to the same contact at Netscape.           Background       Cookies are the mechanism used by most websites to identify and     authenticate a user. If you can steal someone's cookies, you can trick     the server into thinking you are them. Exactly what this gains you     depends on the application and how it is designed. It may gain you     very little, or it may gain you a whole lot (eg. [7]Microsoft Passport     to Trouble). For more information about cookies, see [8]The Unofficial     Cookie FAQ.          Cookies are set with a specific hostname or a domain, so that they are     only sent to that host or domain, with an exception or two that I     won't go into here. They can also be set with a specific path, or with     the secure flag, which means they will only be sent if the connection     is a SSL connection. Normally, this should mean that only the server     that set the cookie, or others it is operating in cooperation with     (eg. in the same domain) can read it.          Mozilla has a bug that lets you bypass this protection and steal     cookies for any domain. This is quite similar to bugs found in     Microsoft Internet Explorer in the past, such as [9]this one and     [10]this one. As has been shown time and time again, there are many     security flaws in many Microsoft products. Sadly, they are far from     being alone. There is almost certainly no web browser out there that     is functional enough to browse a significant percent of current     popular websites and that does not have similar security holes.       Details       The details are very trivial. Loading a URL such as:          http://alive.znep.com%00www.passport.com/cgi-bin/cookies       ...will cause Mozilla to connect to the hostname specified before the     "%00", but send the cookies to the server based on the entire     hostname. The "%00" is the URL encoded version of the null character,     used in C to terminate strings.          This exploit can be used to steal cookies with a specific path set,     and can be used to steal cookies with the secure flag set, by using     the specific path and SSL in the request URL. Note, however, that     cookies set for a specific hostname (eg. "www.passport.com") can not     be stolen using this method, but only cookies set for an entire domain     (eg. ".passport.com").          This bug was first tested on Netscape 6.1 on Windows 2000 and Mozilla     0.9.5 build 2001111503 and 0.9.5 build 20011012 on Linux. It is     expected that all Netscape 6.x and Mozilla versions prior to the     recently released fixed versions are vulnerable.       Example Exploit       An example exploit [11]is available. Very straightforward.       _______________________________________________________________          $Id: index.html,v 1.6 2002/01/22 05:06:04 marcs Exp marcs $       _______________________________________________________________    References       1. http://alive.znep.com/~marcs/security/mozillacookie/#executivesummary     2. http://alive.znep.com/~marcs/security/mozillacookie/#history     3. http://alive.znep.com/~marcs/security/mozillacookie/#background     4. http://alive.znep.com/~marcs/security/mozillacookie/#details     5. http://alive.znep.com/~marcs/security/mozillacookie/#example     6. http://home.netscape.com/security/     7. http://alive.znep.com/~marcs/passport/     8. http://www.cookiecentral.com/faq/     9. http://alive.znep.com/~marcs/security/iecookie1/    10. http://alive.znep.com/~marcs/security/iecookie2/    11. http://alive.znep.com/~marcs/security/mozillacookie/demo.html    

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