Article shows how to make a script that fakes one kind of content when printed with cat, but uses different code when executed:
$ 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!
Posted by Henning Koch to makandra dev (2015-09-25 12:55)