ios/objective C ip spoofing sample

Question

Does anyone know if there's a way to do IP spoofing in an ios/objectiveC/iphone app? I looked online, but couldn't find any way to do this. A few apps on the app store claim to be able to do this, but there is no indication anywhere as to how.

Answer 1

In order to modify an IP header, you need access to what's known as "raw sockets". Raw sockets aren't allowed on most operating system without elevated privileges.

Unfortunately for you, iOS apps don't run with the required privilege for raw sockets. You might be able to do something like this from the simulator running as root, using low level C sockets:

int sockfd = socket(AF_INET, SOCK_RAW, 0);

But you'll get an error if you try to run this on an iOS device (not jailbroken).

Spoofing an IP address has very limited use anyway. When you send data to a server from a spoofed IP address, you never see the response. Using a spoofed IP address, you'll never be able to establish any connection that requires any kind of handshake, including TCP and VPN connections.

About the best use of a spoofed IP address is to perform some kind of denial of service (DOS) attack, hiding your actual attack origin. You could perform a SYN flood, or you could flood UDP services such as DNS. However, you couldn't use it to post to a web server because HTTP requires a TCP connection.

More and more networks are getting smart and not forwarding traffic that doesn't originate from their network, so as time passes, these kinds of attacks will become less practical.