Does this C# block return URL hacking?

Does this C# block return URL hacking?

            if (Url.IsLocalUrl(redirectToAfterLoggingIn) && redirectToAfterLoggingIn.Length > 1 &&
                (redirectToAfterLoggingIn.StartsWith("/") && !redirectToAfterLoggingIn.StartsWith("//")) &&
                return Redirect(redirectToAfterLoggingIn);

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I find it confusing, at best.

How can it be a local URL if it starts with a "/"?

newbiewebSr. Software EngineerAsked:
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Julian HansenCommented:
Because '/' means relative to the web root

<a href="/subfolder/page.html'>Click</a>

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Refers to the same host as the page the link is on relative to the site's web-root.
<a href="//">Another site</a>

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// Refers to an address that is another domain (may be the same domain but is a full URL not a relative path)

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newbiewebSr. Software EngineerAuthor Commented:
So, could redirectToAfterLoggingIn still have a value like:


I am trying to assess the danger of calling the Redirect function, as written.

Should I create a different version of my whitelist check which could attempt to extract a URL to verify, from that partial domain?
Julian HansenCommented:
You can redirect to a local URL using the fully qualified URI i.e.
newbiewebSr. Software EngineerAuthor Commented:
Julian HansenCommented:
You are welcome.
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