TlsInjector.py is a script in python that lets you inject a shellcode in a binary to be executed through TLS callbacks.
As far as I know there isn't any tool that let's you backdoor a binary using this method in an automated way. The fact of using a TLS callback instead of the usual injection techniques has some added advantages; for example, you don’t need to modify the entry point to jump/call to the code cave and then redirect the execution flow to the original program. Another key advantage is that a TLS callback runs the code before the entry point is reached.
The script will accept the shellcode you want to inject and the target binary. The script also includes a payload that let's you inject (though LoadLibrary) an evil DLL. You only need to use the -l option and feed it with the DLL path as a parameter.
More payloads will be included as needed.
The tools is available in Github:
https://github.com/BorjaMerino/tlsInjector
More info:
http://www.shelliscoming.com/2015/06/tls-injector-running-shellcodes-through.html | 
