How to translate this sentence from English, or how is a fake package different from an injection?

Question

WiFi

Here is the original text:

Simplified, against AES-CCMP an adversary can replay and decrypt (but not forge) packets. This makes it possible to hijack TCP streams and inject malicious data into them.

This is how I translated:

Simply put, an attack against AES-CCMP allows packets to be replayed and decrypted (but not forged). This allows you to hijack TCP streams and inject malicious data into them.

Why is it possible to make an injection, but not to fake it?

Answer 1

Why is it possible to make an injection, but not to fake it?

Because being in the middle, you can inject previously intercepted packets (replay) into the connection. But in order to fake a package, you need to know the key.