@zhenech You reminded me about this one

https://www.openwall.com/lists/oss-security/2015/09/17/5

```
$ printf '#!/bin/bash\necho doing something evil!\nexit\n\033[2Aecho
doing something very nice!\n' > backdoor.sh
$ chmod +x backdoor.sh
$ cat backdoor.sh
#!/bin/bash
echo doing something very nice!
$ ./backdoor.sh
doing something evil!
```

Nightmarish it is.

P.S. Also I had to dig through my G+ archives to find it, so thank you for bringing back some awesome memories :)