# Alien Transmission 1**Category:** Forensics/OSINT
**Points:** 219
**Description:**> I was listening to my radio the other day and received this strange message...I think it came from an alien?>> ~BobbaTea#6235>> **Given:** command_1
## WriteupListening to the message doesn't really give us much, but we have a few ways totry to analyze this. First thing I do is pop it open in **Sonic Visualizer** to seeif anything pops up in the spectrogram or if I can see anything interesting likea pattern in the frequencies, but nothing special there.
After a little digging, I remembered there is a thing called Slow-Scan Television(SSTV)! This is a form of steganography used nowadays to hide JPEGsor PNGs in WAV audio files, but it was originally used to transmit images via radiosignals from the moon and back. There is a Wiki page on SSTV and is worth the read!
There is a writeup done on a similar challenge from picoCTF 2019, which I willprovide in the references because I pretty much go off of it. There is a Linuxapplication called Qsstv, which looks for SSTV images in a wav file.
```$ apt-get install qsstv$ pactl load-module module-null-sink sink_name=virtual-cable22$ pavucontrol # A GUI will pop-up, go to the "Output Devices" tab to verify that you have the "Null Output" device$ qsstv # The program GUI will pop-up, go to "Options" -> "Configuration" -> "Sound" and select the "PulseAudio" Audio Interface$ # Back in the pavucontrol GUI, select the "Recording" tab and specify that QSSTV should capture audio from the Null Output$ paplay -d virtual-cable <wav file>```

## FlagrgbCTF{s10w_2c4n_1s_7h3_W4V3}
## Resources[m00nwalk writeup](https://github.com/Dvd848/CTFs/blob/master/2019_picoCTF/m00nwalk.md)
[SSTV Wiki](https://en.wikipedia.org/wiki/Slow-scan_television)