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Re: Feature suggestion to block Curl from connecting reserved and private IP addresses

From: Daniel Stenberg via curl-library <>
Date: Tue, 14 Dec 2021 09:22:38 +0100 (CET)

On Tue, 14 Dec 2021, Ayesh Karunaratne via curl-library wrote:

> With the addition of CURLOPT_PREREQFUNCTION, one could write a callback
> function to selectively block requests to certain IP/port ranges. This is
> great, and I think it comes handy when trying to prevent SSRF
> vulnerabilities by blocking the request if it directs to an IP address that
> is reserved or private.

Isn't the solution to this, and a remedy to many other attacks at the same
time, rather to use a secure protocol? If you use a TLS or SSH based protocol,
it doesn't matter if someone manages to trick curl to connect to the wrong
address as it won't survive the handshake anyway!

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Received on 2021-12-14