hardening-check - check binaries for security hardening
features
hardening-check [options] [ELF ...]
Examine a given set of ELF binaries and check for several security
hardening features, failing if they are not all found.
This utility checks a given list of ELF binaries for several
security hardening features that can be compiled into an executable. These
features are:
- Position
Independent Executable
- This indicates that the executable was built in such a way (PIE) that the
"text" section of the program can be relocated in memory. To
take full advantage of this feature, the executing kernel must support
text Address Space Layout Randomization (ASLR).
- Stack
Protected
- This indicates that there is evidence that the ELF was compiled with the
gcc(1) option -fstack-protector (e.g. uses
__stack_chk_fail). The program will be resistant to having its
stack overflowed.
When an executable was built without any character arrays
being allocated on the stack, this check will lead to false alarms
(since there is no use of __stack_chk_fail), even though it was
compiled with the correct options.
- Fortify Source
functions
- This indicates that the executable was compiled with
-D_FORTIFY_SOURCE=2 and -O1 or higher. This causes certain
unsafe glibc functions with their safer counterparts (e.g. strncpy
instead of strcpy), or replaces calls that are verifiable at
runtime with the runtime-check version (e.g. __memcpy_chk insteade
of memcpy).
When an executable was built such that the fortified versions
of the glibc functions are not useful (e.g. use is verified as safe at
compile time, or use cannot be verified at runtime), this check will
lead to false alarms. In an effort to mitigate this, the check will pass
if any fortified function is found, and will fail if only unfortified
functions are found. Uncheckable conditions also pass (e.g. no functions
that could be fortified are found, or not linked against glibc).
- Read-only
relocations
- This indicates that the executable was build with -Wl,-z,relro to
have ELF markings (RELRO) that ask the runtime linker to mark any regions
of the relocation table as "read-only" if they were resolved
before execution begins. This reduces the possible areas of memory in a
program that can be used by an attacker that performs a successful memory
corruption exploit.
- Immediate
binding
- This indicates that the executable was built with -Wl,-z,now to
have ELF markings (BIND_NOW) that ask the runtime linker to resolve all
relocations before starting program execution. When combined with RELRO
above, this further reduces the regions of memory available to memory
corruption attacks.
- --nopie,
-p
- Do not require that the checked binaries be built as PIE.
- --nostackprotector,
-s
- Do not require that the checked binaries be built with the stack
protector.
- --nofortify,
-f
- Do not require that the checked binaries be built with Fortify
Source.
- --norelro,
-r
- Do not require that the checked binaries be built with RELRO.
- --nobindnow,
-b
- Do not require that the checked binaries be built with BIND_NOW.
- --nocfprotection,
-b
- Do not require that the checked binaries be built with control flow
protection.
- --quiet,
-q
- Only report failures.
- --verbose,
-v
- Report verbosely on failures.
- --report-functions,
-R
- After the report, display all external functions needed by the ELF.
- --find-libc-functions,
-F
- Instead of the regular report, locate the libc for the first ELF on the
command line and report all the known "fortified" functions
exported by libc.
- --color,
-c
- Enable colorized status output.
- --lintian,
-l
- Switch reporting to lintian-check-parsable output.
- --debug
- Report some debugging during processing.
- --help, -h,
-?
- Print a brief help message and exit.
- --man, -H
- Print the manual page and exit.
When all checked binaries have all checkable hardening features
detected, this program will finish with an exit code of 0. If any check
fails, the exit code with be 1. Individual checks can be disabled via
command line options.
Kees Cook <kees@debian.org>
Copyright 2009-2013 Kees Cook <kees@debian.org>.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 or later.