Azure AD B2C容易受到开放重定向的影响吗? [英] Azure AD B2C vulnerable to Open Redirect?

问题描述

我正在使用OWIN&OpenId使用Azure AD B2C对我的Web应用程序的用户进行身份验证，Startup.Auth.cs具有如下代码:

I am using OWIN & OpenId to authenticate users for my web application using Azure AD B2C, the Startup.Auth.cs has code like so :

app.UseOpenIdConnectAuthentication(
            new OpenIdConnectAuthenticationOptions
            {
                 MetadataAddress = string.Format(AadInstance, Tenant, policy),
                AuthenticationType = policy,
                ClientId = clientId,
                Authority = authority,
                PostLogoutRedirectUri = postLogoutRedirectUri,
                RedirectUri = postLogoutRedirectUri,
                Notifications = new OpenIdConnectAuthenticationNotifica....

登出后，将导致重定向到postLogoutRedirectUrl

On signout, it causes a redirect to the postLogoutRedirectUrl like so

https://login.microsoftonline.com/MY_TENANT/oauth2/logout?p=my_policy&post_logout_redirect_uri=https%3A%2F%2Fgoogle.com%2F

门户网站的重定向Uri中存在注销后重定向的URI.

The post logout redirect URI is present in the redirect Uri in the portal.

如果我停止浏览器并将地址栏中的发布注销uri更改为https％3A％2F％2Fevil.com％2F，即使此URL

If I stop the browser and change the post logout uri in the address bar to https%3A%2F%2Fevil.com%2F, the redirect happens properly even though this url https://evil.com/ is not in the allowed redirect uri.

为什么AD B2C不停止重定向?这不容易受到攻击吗?

Why is AD B2C not stopping the redirect ? is this not open to vulnerability ?

推荐答案

使用Azure AD B2C登录时，B2C服务会将令牌发送到"redirect_uri"(应用程序).由于令牌需要保持安全性，因此B2C服务会要求您将其应将令牌发送到的URL列入白名单.

When you sign in using Azure AD B2C, the B2C service sends a token to the "redirect_uri" (the app). Since a token needs to remain secure, the B2C service asks you to whitelist the URL's where it should send the token to.

退出时，没有任何安全措施从B2C服务传输回应用程序.因此，即使将用户重定向到恶意站点，也不会丢失任何安全性.

When you are signing out, nothing secure is being transmitted from the B2C service back to the app. Therefore, even if a user is redirected to a malicious site, nothing secure is lost.

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