CodeSOD: A Well Known Address

Amanda's company wanted to restrict access to a service by filtering on the requestor's IP address. Yes, this is a terrible idea. So they wanted to make it a bit smarter, and also filter on various subnets. But they had a LOT of different subnets.

So the result was this:

ok = 0ip = Request.ServerVariables("REMOTE_ADDR")if ip = "xxx.xxx.xxx.xxx" or ip = "xxx.xxx.xxx.xxx" or ip = "xxx.xxx.xxx.xxx" or ip = "xxx.xxx.xxx.xxx" or ip = "xxx.xxx.xxx.xxx" or ip = "xxx.xxx.xxx.xxx" or ip = "xxx.xxx.xxx.xxx" or ip = "xxx.xxx.xxx.xxx" or ip = "xxx.xxx.xxx.xxx" or ip = "xxx.xxx.xxx.xxx" or ip = "xxx.xxx.xxx.xxx" then ok = 1end ifip2 = Split(ip,".")ip3 = ip2(0) &"."& ip2(1) &"."& ip2(2)if ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" then ok = 1end ifif ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" or ip3 = "xxx.xxx.xxx" then ok = 1end ifif ok = 1 then response.redirect "http://www.somedomain.com/something/that/is/meant/to/be/private"else response.redirect "index.asp?error=1"end if

Imagine that each xxx in there is part of an IP address. Whitespace as in original, apologies to your scrollbar.

This code is fairly old- classic ASP, but it was still in use as of a decade ago. Which, it happens, is when Amanda worked on it. She did the sane thing and deleted this block and just used the authentication system that the application already had. Customers were happy, as it meant they didn't need to get their IP address allowlisted, they could just sign in.

At least one manager was unhappy, because they were convinced that by allowlisting, they were enforcing a "per seat" license- "Every computer has a unique IP address!" they insisted. "Without this check, they could sign on from any computer, anywhere!"

Fortunately, that manager was eventually talked down when someone suggested that this gives each user their own account, and thus prevents two people from sharing the same computer.

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