HTB Cyber Apocalypse 2023 - (Hardware) Timed Transmission

‘Timed Transmission’ was one of the challenges in the ‘Hardware’ category at HTB’s Cyber Apocalypse 2023.
Its difficulty was ‘Very easy’ so it was a very simple challenge. This makes it a very good challenge to try for people who tried their first CTF.

For this challenge, we got an archive containing a single file: Captured_Signals.sal.

After searching for it online, I found out that this extension is used by Saleae’s Logic2 software.
This can be downloaded from the vendor’s website (here)

After installing Logic2, I opened the Captured_Signals.sal file and I could see 5 signals being captured.

After I spent almost half an hour trying to find a protocol that uses those signals like that (JTAG was a close one in my mind), I finally tried zooming out.

This looks a lot like the beginning of a flag: HTB{b39

So I scrolled through the timeline to see if the whole flag can be found like this.

Here’s the second part: 1N_tH3_

The third part: HArdWA Fourth part: r3_QU3

And the last part: 3St}

And we put those together to get the full flag: HTB{b391N_tH3_HArdWAr3_QU3St}
This was easy … once I zoomed out

More hardware challenges

These are the other hardware challenges from this CTF

• Hardware 1/5 - Very Easy - Critical Flight
• Hardware 2/5 - Very Easy - Timed Transmission (you are here)
• Hardware 3/5 - Easy - Debug
• Hardware 4/5 - Easy - Secret Code
• Hardware 5/5 - Medium - HM74