checksec
========

Checksec is a bash script to check the properties of executables (like PIE, RELRO, Canaries, ASLR, Fortify Source).
It has been originally written by Tobias Klein and the original source is available here: http://www.trapkit.de/tools/checksec.html

Updates
-------
  ** MAJOR UPDATES ** 2.1.0
   - Changed structure to be more modular and switched to getopts so options can be in any order.   e.g. format=json can be at the end now, however.
   - All options now require `--$option=$value` instead of `--$option $value`
   - --extended option now includes clang CFI and safe stack checks

   Last Update: 2022-05-27

For OSX
-------
 Most of the tools do not work on mach-O binaries or the OSX kernel, so it is not supported

Manually verify checksec

`openssl dgst -sha256 -verify checksec.pub -signature checksec.sig checksec`

Examples
--------

**normal (or --format=cli)**

    $checksec --file=/bin/ls
    RELRO           STACK CANARY      NX            PIE             RPATH      RUNPATH      FILE
    Partial RELRO   Canary found      NX enabled    No PIE          No RPATH   No RUNPATH   /bin/ls

**csv**

    $ checksec --output=csv --file=/bin/ls
    Partial RELRO,Canary found,NX enabled,No PIE,No RPATH,No RUNPATH,/bin/ls

**xml**

    $ checksec --output=xml --file=/bin/ls
    <?xml version="1.0" encoding="UTF-8"?>
    <file relro="partial" canary="yes" nx="yes" pie="no" rpath="no" runpath="no" filename='/bin/ls'/>

**json**

    $ checksec --output=json --file=/bin/ls
    { "file": { "relro":"partial","canary":"yes","nx":"yes","pie":"no","rpath":"no","runpath":"no","filename":"/bin/ls" } }

**Fortify test in cli**

    $ checksec --fortify-proc=1
    * Process name (PID)                         : init (1)
    * FORTIFY_SOURCE support available (libc)    : Yes
    * Binary compiled with FORTIFY_SOURCE support: Yes

    ------ EXECUTABLE-FILE ------- . -------- LIBC --------
    FORTIFY-able library functions | Checked function names
    -------------------------------------------------------
    fdelt_chk                      | __fdelt_chk
    read                           | __read_chk
    syslog_chk                     | __syslog_chk
    fprintf_chk                    | __fprintf_chk
    vsnprintf_chk                  | __vsnprintf_chk
    fgets                          | __fgets_chk
    strncpy                        | __strncpy_chk
    snprintf_chk                   | __snprintf_chk
    memset                         | __memset_chk
    strncat_chk                    | __strncat_chk
    memcpy                         | __memcpy_chk
    fread                          | __fread_chk
    sprintf_chk                    | __sprintf_chk

    SUMMARY:

    * Number of checked functions in libc                : 78
    * Total number of library functions in the executable: 116
    * Number of FORTIFY-able functions in the executable : 13
    * Number of checked functions in the executable      : 7
    * Number of unchecked functions in the executable    : 6


**Kernel test in Cli**

    $ checksec --kernel
    * Kernel protection information:

    Description - List the status of kernel protection mechanisms. Rather than
    inspect kernel mechanisms that may aid in the prevention of exploitation of
    userspace processes, this option lists the status of kernel configuration
    options that harden the kernel itself against attack.

    Kernel config: /proc/config.gz

        GCC stack protector support:            Enabled
        Strict user copy checks:                Disabled
        Enforce read-only kernel data:          Disabled
        Restrict /dev/mem access:               Enabled
        Restrict /dev/kmem access:              Enabled

    * Kernel Heap Hardening: No KERNHEAP

    The KERNHEAP hardening patchset is available here:
     https://www.subreption.com/kernheap/


**Kernel Test in XML**

    $ checksec --output=xml --kernel
    <?xml version="1.0" encoding="UTF-8"?>
    <kernel config='/boot/config-3.11-2-amd64' gcc_stack_protector='yes' strict_user_copy_check='no' ro_kernel_data='yes' restrict_dev_mem_access='yes' restrict_dev_kmem_access='no'>
        <kernheap config='no' />
    </kernel>

**Kernel Test in Json**

    $ checksec --output=json --kernel
     { "kernel": { "KernelConfig":"/boot/config-3.11-2-amd64","gcc_stack_protector":"yes","strict_user_copy_check":"no","ro_kernel_data":"yes","restrict_dev_mem_access":"yes","restrict_dev_kmem_access":"no" },{ "kernheap_config":"no" } }

Using with Cross-compiled Systems
---------------------------------------
The checksec tool can be used against cross-compiled target file-systems offline.  Key limitations to note:
* Kernel tests - require you to execute the script on the running system you'd like to check as they directly access kernel resources to identify system configuration/state. You can specify the config file for the kernel after the -k option.

* File check -  the offline testing works for all the checks but the Fortify feature.  Fortify, uses the running system's libraries vs those in the offline file-system. There are ways to workaround this (chroot) but at the moment, the ideal configuration would have this script executing on the running system when checking the files.

The checksec tool's normal use case is for runtime checking of the systems configuration.  If the system is an embedded target, the native binutils tools like readelf may not be present.  This would restrict which parts of the script will work.

Even with those limitations, the amount of valuable information this script provides, still makes it a valuable tool for checking offline file-systems.
