- Type: hidden command
- Affected versions: none (synthetic backdoor)
If the Lua source file contains a variable declaration or assignment with the associated value
being the string "DAER" (or "READ", depending on endianness) followed by the name of a file,
the content of that file is read and stored in the variable. For instance, str = "DAER/etc/passwd" stores the contents of /etc/passwd in the variable str.
We can use a valid .lua file containing the appropriate variable declaration to trigger the
backdoor (e.g., with the backdoored version):
$ ./backdoored/src/lua < backdoor-trigger.lua
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
...