SharePoint 2010 - All Users are logged in as System Account

I've got a very strange problem with my SharePoint 2010 Web application.

Every users are now logged on my sites as System Account (SharePoint\system). They can access all content of a开发者_如何转开发ll site collections whatever security is associated to their domain user account.

The ONLY change that happened is that someone changed the App Pool identity password... I still don't know who did this btw...

I've read that this might occur when the Web Application AppPool is running with the farm admin account but thats not my case.

Does anyone ever encounter this problem?? Any hint or ideas would be greatly appreciated.

Thanks,

JP

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I found my problem. My web site in IIS was running under the special AppPool account so no users were asked for credentials. I switched back the settings (in basic settings of the web site) to Application user.

I don't know what happen on my environnement, many people can access this server so maybe someone did a few test on my production environnement... I'm not the one managing security so I can't do anything about it... anyway.

Thanks!