Checksec checks 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. Over time this has expanded in feature set and has now moved from Bash to Golang.
Version: 3.0.1
Checksec was originally released with 1.0 in early 2009 and has been used for validating binary checks of Linux systems for over a decade. Over time as more checks were supported and Linux distributions have changed, this has brought more dependencies into checksec. Adding more and more dependenies to be able to check the security flags of files, it not an ideal solution for systems with minor dependencies including embedded systems, distroless containers, and cross platform checks.
- Feature partial between the bash version and the golang version will be mostly supported.
- Adding support for yaml output
- Removing support for CSV
- JSON and XML will still both be supported
- Much faster results. When checking 694 files in a directory
- bash: real 0m10.348s
- golang: real 0m0.691s
Checksec can scan linux files from OSX however, some checks may be limited due to OS dependencies on resources like glibc.
normal (or --format=cli)
$checksec file /bin/ls
RELRO Stack Canary NX PIE RPATH RUNPATH Symbols FORTIFY Fortified Fortifiable Name
Partial RELRO Canary Found NX enabled PIE Enabled No RPATH No RUNPATH No Symbols No 0 14 /bin/ls
yaml
$ checksec file /bin/ls --output yaml
- checks:
canary: Canary Found
fortified: "0"
fortify_source: "No"
fortifyable: "14"
nx: NX enabled
pie: PIE Enabled
relro: Partial RELRO
rpath: No RPATH
runpath: No RUNPATH
symbols: No Symbols
name: /bin/ls
xml
$ checksec file /bin/ls --output xml
<SecurityCheck>
<Name>/bin/ls</Name>
<Checks>
<Canary>Canary Found</Canary>
<Fortified>0</Fortified>
<FortifyAble>14</FortifyAble>
<FortifySource>No</FortifySource>
<NX>NX enabled</NX>
<PIE>PIE Enabled</PIE>
<Relro>Partial RELRO</Relro>
<RPath>No RPATH</RPath>
<RunPath>No RUNPATH</RunPath>
<Symbols>No Symbols</Symbols>
</Checks>
</SecurityCheck>
json
$ checksec file /bin/ls --output json
[
{
"checks": {
"canary": "Canary Found",
"fortified": "0",
"fortify_source": "No",
"fortifyable": "14",
"nx": "NX enabled",
"pie": "PIE Enabled",
"relro": "Partial RELRO",
"rpath": "No RPATH",
"runpath": "No RUNPATH",
"symbols": "No Symbols"
},
"name": "/bin/ls"
}
]
Fortify test in cli
$ checksec fortifyProc 1
_____ _ _ ______ _____ _ __ _____ ______ _____
/ ____| | | | ____/ ____| |/ // ____| ____/ ____|
| | | |__| | |__ | | | ' /| (___ | |__ | |
| | | __ | __|| | | < \___ \| __|| |
| |____| | | | |___| |____| . \ ____) | |___| |____
\_____|_| |_|______\_____|_|\_\_____/|______\_____|
* FORTIFY_SOURCE support available (libc): Yes
* Binary compiled with FORTIFY_SOURCE support: No
------ EXECUTABLE-FILE ------- | -------- LIBC --------
Fortifiable library functions | Checked function names
Coming Soon
SUMMARY
* Number of checked functions in libc : 18
* Total number of library functions in the executable: 2011
* Number of Fortifiable functions in the executable : 12
* Number of checked functions in the executable : 0
* Number of unchecked functions in the executable : 12
Kernel test in Cli
$ checksec kernel
_____ _ _ ______ _____ _ __ _____ ______ _____
/ ____| | | | ____/ ____| |/ // ____| ____/ ____|
| | | |__| | |__ | | | ' /| (___ | |__ | |
| | | __ | __|| | | < \___ \| __|| |
| |____| | | | |___| |____| . \ ____) | |___| |____
\_____|_| |_|______\_____|_|\_\_____/|______\_____|
Kernel configs only print what is supported by the specific kernel/kernel config
Description Value Check Type Config Key
Virtually-mapped kernel stack Disabled Kernel Config CONFIG_VMAP_STACK
Harden str/mem functions Disabled Kernel Config CONFIG_FORTIFY_SOURCE
Restrict Kernel RWX Enabled Kernel Config CONFIG_STRICT_KERNEL_RWX
Restrict /dev/mem access Enabled Kernel Config CONFIG_STRICT_DEVMEM
SELinux Kernel Flag Disabled Kernel Config CONFIG_SECURITY_SELINUX
Emulate privileged access never Disabled Kernel Config CONFIG_ARM64_SW_TTBR0_PAN
Restrict I/O access to /dev/mem Disabled Kernel Config CONFIG_IO_STRICT_DEVMEM
Kernel Heap Randomization Disabled Kernel Config CONFIG_COMPAT_BRK
Stack Protector Strong Disabled Kernel Config CONFIG_STACKPROTECTOR_STRONG
Hardened Usercopy Disabled Kernel Config CONFIG_HARDENED_USERCOPY
Restrict Module RWX Enabled Kernel Config CONFIG_STRICT_MODULE_RWX
Address space layout randomization Disabled Kernel Config CONFIG_RANDOMIZE_BASE
Randomize address of kernel image Disabled Kernel Config CONFIG_RANDOMIZE_BASE
Stack Protector Disabled Kernel Config CONFIG_STACKPROTECTOR
Unmap kernel in userspace (KAISER) Enabled Kernel Config CONFIG_UNMAP_KERNEL_AT_EL0
SLAB freelist randomization Disabled Kernel Config CONFIG_SLAB_FREELIST_RANDOM
SELinux Enabled Disabled SELinux SELinux
Protected symlinks Enabled Sysctl fs.protected_symlinks
Protected hardlinks Enabled Sysctl fs.protected_hardlinks
Ipv4 reverse path filtering Disabled Sysctl net.ipv4.conf.all.rp_filter
YAMA Unknown Sysctl kernel.yama.ptrace_scope
Exec Shield Unknown Sysctl kernel.exec-shield
Unprivileged BPF Disabled Disabled Sysctl kernel.unprivileged_bpf_disabled
Vanilla Kernel ASLR Enabled Sysctl kernel.randomize_va_space
Dmesg Restrictions Enabled Sysctl kernel.dmesg_restrict
Kernel Pointer Restrictions Disabled Sysctl kernel.kptr_restrict
Protected fifos Disabled Sysctl fs.protected_fifos
Protected regular Disabled Sysctl fs.protected_regular
Performance events by normal users Enabled Sysctl kernel.perf_event_paranoid
Disable Autoload TTY Line Disciplines Disabled Sysctl dev.tty.ldisc_autoload
Disable Legacy TIOCSTI Disabled Sysctl dev.tty.legacy_tiocsti
Kernel Test in XML
$ checksec kernel --output xml
<KernelCheck>
<Name>CONFIG_IO_STRICT_DEVMEM</Name>
<Description>Restrict I/O access to /dev/mem</Description>
<Value>Disabled</Value>
<CheckType>Kernel Config</CheckType>
</KernelCheck>
<KernelCheck>
<Name>CONFIG_STRICT_MODULE_RWX</Name>
<Description>Restrict Module RWX</Description>
<Value>Enabled</Value>
<CheckType>Kernel Config</CheckType>
</KernelCheck>
<KernelCheck>
<Name>CONFIG_SECURITY_SELINUX</Name>
<Description>SELinux Kernel Flag</Description>
<Value>Disabled</Value>
<CheckType>Kernel Config</CheckType>
</KernelCheck>
Kernel Test in Json
$ checksec kernel --output json
[
{
"desc": "Hardened Usercopy",
"name": "CONFIG_HARDENED_USERCOPY",
"type": "Kernel Config",
"value": "Disabled"
},
{
"desc": "Harden str/mem functions",
"name": "CONFIG_FORTIFY_SOURCE",
"type": "Kernel Config",
"value": "Disabled"
},
{
"desc": "Restrict Kernel RWX",
"name": "CONFIG_STRICT_KERNEL_RWX",
"type": "Kernel Config",
"value": "Enabled"
},
{
"desc": "Virtually-mapped kernel stack",
"name": "CONFIG_VMAP_STACK",
"type": "Kernel Config",
"value": "Disabled"
},
{
"desc": "SELinux Kernel Flag",
"name": "CONFIG_SECURITY_SELINUX",
"type": "Kernel Config",
"value": "Disabled"
}
]
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. By default, 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. An other option is to specify where the cross-compiled libc is located through the -libc option.
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.