* Posts by ankitpati

2 posts • joined 11 Sep 2019

The NetCAT is out of the bag: Intel chipset exploited to sniff SSH passwords as they're typed over the network


Re: Press Ctrl + S to Save Yourself Against this Exploit

Works fine.

Simple test:

1. Open a terminal on any Linux system. iTerm2 on macOS does not support flow control.

2. Press Ctrl + S.

3. Blindly type `sleep 5` (ignore the back-ticks, and mind the space in between).

4. Press Enter/Return.

5. Wait 10 seconds.

6. Press Ctrl + Q.

7. Observe what happens!


Press Ctrl + S to Save Yourself Against this Exploit

There’s a very simple mitigation against this exploit, already built right into (almost) every terminal (and terminal emulator) since the first (physical) one: Flow Control.

Just press Ctrl + S before entering sensitive information into a terminal, and press Ctrl + Q when done.

For improved usability, avoid using this with non-sensitive information, like regular UNIX commands. Only use for passwords, and perhaps secret file/directory names on a web server.

What happens is that the terminal queues your input between those two keystrokes, and sends it all at once, obliterating any timing information. Ctrl + S and Ctrl + Q are themselves not sent over the wire.

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