Shc (shell script compiler)

SHC is a shell script compiler written in C programming language. The Shell Script Compiler (SHC) converts linux shell scripts directly into executable binaries. Compiling shell scripts into binaries provides protection against accidental changes, source modification and renders a way of hiding source code written in linux shell scripting language.

Mechanism

SHC takes a shell script which is specified on the command line by $[-ffilename]$ option and produces a C source code of the script. The generated source code is then compiled and linked to produce a binary executable. Thus it's a two step process where, at first step, it creates a $filename.x.c$ file of the shell script file $filename$. Then it is compiled with $cc-\$CFLAGSfilename.x.c$ and thus build the binary from a C source code with the default C compiler available in any system.

The compiled binary will still be dependent on the shell specified in the first line of the shell code (i.e Shebang: #!/bin/sh or such), thus shc does not create completely independent binaries.shc itself is not a compiler such as cc, it rather encodes and encrypts a shell script and generates C source code with the added expiration capability. It then uses the system compiler to compile a stripped binary which behaves exactly like the original script. Upon execution, the compiled binary will decrypt and execute the code with the shells' -c option.

Versions

Available Versions

Version	Release Date	Changes
shc-3.9.2	21-Aug-2015	Added Busybox support ( -B flag to compile for Busybox).
shc-3.9.1	03-Apr-2015	Set -T option as default, and renaming it to -U to its counter logic
shc-3.9.0	01-Apr-2015	Adding output file option with [-o filename] and bug fixes
shc-3.8.9	04-Dec-2013	Fixing a long-standing bug making the source not hidden
shc-3.8.7	10-Feb-2010	Bug on 64bit systems with expiration dates
shc-3.8.5	10-Feb-2010
shc-3.8.3	10-Jul-2006	Fixed untraceable() problems on FreeBSD
shc-3.8.2	06-Jul-2006	Read permission of the script.x exposes it to disassembling. Group and others read permission is now removed by default.
shc-3.7	28-Jun-2005	Removed all strings in the compiled script. Improved program output and error messages. The -m option allows to define the *complete* expiration message. Updated manpage shc.1
shc-3.6	16-Jun-2005	Two new options: -D switch on Debug exec calls. -T switch off unTraceable.
shc-3.4	19-Jun-2003	Remove "bad alignment" problem on AIX and other systems. Where exists, use /proc/<pid>/as in untraceable.
shc-3.3	21-Apr-2003	Prevent to ptrace the process
shc-3.2	05-Aug-2002	Find ancient pclose that must be fclose
shc-3.1	05-Aug-2002	Fixed a misbehavior on scripts with a in-frist-line option equal to "end of options" (i.e. #!/bin/sh -- ) GCC "warning: return type of `main' is not `int'" removed
shc-2.4	05-Aug-2002

Alternatives

1. obfs
2. shellcrypt

External links

1. https://raw.githubusercontent.com/neurobin/shc/release/README.md
2. http://www.l0d.org/Decrypt_an_shc_crypted_file-4.html
3. http://neurobin.github.io/shc

References