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13 changes: 13 additions & 0 deletions nxc/helpers/path.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,13 @@
from pathlib import PurePosixPath


def sanitize_filename(name: str) -> str:
"""Strip path traversal components from an SMB filename.

Follows the pattern from spider_plus.py — filters '..' and '.' from
PurePosixPath.parts to prevent directory traversal attacks from
malicious SMB servers.
"""
parts = PurePosixPath(name.replace("\\", "/")).parts
clean = [p for p in parts if p not in ("..", ".", "/")]
return str(PurePosixPath(*clean)) if clean else ""
107 changes: 97 additions & 10 deletions nxc/protocols/smb.py
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,9 @@
import re
import struct
import ipaddress
from pathlib import Path

from nxc.helpers.path import sanitize_filename
from Cryptodome.Hash import MD4
from textwrap import dedent

Expand Down Expand Up @@ -35,7 +38,7 @@
from impacket.dcerpc.v5.dtypes import NULL
from impacket.dcerpc.v5.dcomrt import DCOMConnection
from impacket.dcerpc.v5.dcom.wmi import CLSID_WbemLevel1Login, IID_IWbemLevel1Login, IWbemLevel1Login
from impacket.smb3structs import FILE_SHARE_WRITE, FILE_SHARE_DELETE, SMB2_0_IOCTL_IS_FSCTL
from impacket.smb3structs import FILE_READ_DATA, FILE_WRITE_DATA, FILE_SHARE_WRITE, FILE_SHARE_DELETE, SMB2_0_IOCTL_IS_FSCTL
from impacket.dcerpc.v5 import tsts as TSTS

from nxc.config import process_secret, host_info_colors, check_guest_account
Expand Down Expand Up @@ -1944,24 +1947,108 @@ def put_file(self):
for src, dest in self.args.put_file:
self.put_file_single(src, dest)

def get_file_single(self, remote_path, download_path):
def download_file(self, share_name, remote_path, dest_file, access_mode=FILE_READ_DATA):
try:
self.logger.debug(f"Getting file from {share_name}:{remote_path} with access mode {access_mode}")
self.conn.getFile(share_name, remote_path, dest_file, shareAccessMode=access_mode)
return True
except SessionError as e:
if "STATUS_SHARING_VIOLATION" in str(e):
self.logger.debug(f"Sharing violation on {remote_path}: {e}")
else:
self.logger.debug(f"SessionError when attempting to download file {remote_path}: {e}")
return False
except Exception as e:
self.logger.debug(f"Other error when attempting to download file {remote_path}: {e}")
return False

def get_file_single(self, remote_path, download_path, silent=False):
share_name = self.args.share
self.logger.display(f'Copying "{remote_path}" to "{download_path}"')
if not silent:
self.logger.display(f"Copying '{remote_path}' to '{download_path}'")
if self.args.append_host:
download_path = f"{self.hostname}-{remote_path}"
with open(download_path, "wb+") as file:
try:
self.conn.getFile(share_name, remote_path, file.write)
self.logger.success(f'File "{remote_path}" was downloaded to "{download_path}"')
except Exception as e:
self.logger.fail(f'Error writing file "{remote_path}" from share "{share_name}": {e}')
if os.path.getsize(download_path) == 0:
os.remove(download_path)
if self.download_file(share_name, remote_path, file.write):
if not silent:
self.logger.success(f"File '{remote_path}' was downloaded to '{download_path}'")
else:
self.logger.debug("Opening with READ alone failed, trying to open file with READ/WRITE access")
if self.download_file(share_name, remote_path, file.write, FILE_READ_DATA | FILE_WRITE_DATA):
if not silent:
self.logger.success(f"File '{remote_path}' was downloaded to '{download_path}'")
else:
if not silent:
self.logger.fail(f"Error downloading file '{remote_path}' from share '{share_name}'")

def get_file(self):
for src, dest in self.args.get_file:
self.get_file_single(src, dest)

def download_folder(self, folder, dest, recursive=False, silent=False, base_dir=None, ignore_empty=False):
folder = ntpath.normpath(folder)
self.logger.debug(f"Downloading folder with args: {folder}, {dest}, Recursive: {recursive}, Silent: {silent}, Base dir: {base_dir}, Ignore empty: {ignore_empty}")
base_folder = os.path.basename(folder)
self.logger.debug(f"Base folder: {base_folder}")

try:
items = self.conn.listPath(self.args.share, ntpath.join(folder, "*"))
except SessionError as e:
self.logger.error(f"Error listing folder '{folder}': {e}")
return
self.logger.debug(f"{len(items)} items in folder: {items}")

filtered_items = [item for item in items if item.get_longname() not in [".", ".."]]

# create local directory structure regardless of content; download empty folders by default
# change the Windows path to Linux and then join it with the base directory to get our actual save path
relative_path = os.path.join(*folder.replace(base_dir or folder, "").lstrip("\\").split("\\"))
local_folder_path = os.path.join(dest, relative_path)

if not filtered_items and ignore_empty:
self.logger.debug(f"Skipping empty folder '{folder}'")
return

# create the directory for this folder
os.makedirs(local_folder_path, exist_ok=True)
if not filtered_items and not silent:
self.logger.display(f"Created empty directory '{local_folder_path}'")

for item in filtered_items:
item_name = sanitize_filename(item.get_longname())
if not item_name:
self.logger.fail(f"Path traversal detected in '{item.get_longname()}', skipping")
continue
dir_path = ntpath.normpath(ntpath.join(folder, item_name))
self.logger.debug(f"Parsing item: {item_name}, {dir_path}")

if item.is_directory() and recursive:
self.logger.debug(f"Found new directory to parse: {dir_path}")
self.download_folder(dir_path, dest, recursive, silent, base_dir or folder, ignore_empty)
elif not item.is_directory():
remote_file_path = ntpath.join(folder, item_name)
local_file_path = os.path.join(local_folder_path, item_name)
# Defense-in-depth: verify path stays under destination
resolved = Path(local_file_path).resolve()
if not str(resolved).startswith(str(Path(dest).resolve()) + os.sep):
self.logger.fail(f"Path traversal detected in '{item_name}', skipping")
continue
self.logger.debug(f"{dest=} {remote_file_path=} {relative_path=} {local_folder_path=} {local_file_path=}")

try:
self.get_file_single(remote_file_path, local_file_path, silent)
except FileNotFoundError:
self.logger.fail(f"Error downloading file '{remote_file_path}' due to file not found (probably a race condition between listing and downloading)")

def get_folder(self):
recursive = self.args.recursive
ignore_empty = self.args.ignore_empty_folders
self.logger.debug(f"Recursive option set to {recursive}")
self.logger.debug(f"Ignore empty folders option set to {ignore_empty}")
for folder, dest in self.args.get_folder:
self.download_folder(folder, dest, recursive, self.args.silent, None, ignore_empty)
self.logger.success(f"Folder '{folder}' was downloaded to '{dest}'")

def enable_remoteops(self, regsecret=False):
try:
if regsecret:
Expand Down
5 changes: 4 additions & 1 deletion nxc/protocols/smb/proto_args.py
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
from argparse import _StoreTrueAction, _StoreAction
from argparse import BooleanOptionalAction, _StoreTrueAction, _StoreAction
from nxc.helpers.args import DisplayDefaultsNotNone, DefaultTrackingAction, get_conditional_action


Expand Down Expand Up @@ -90,6 +90,9 @@ def proto_args(parser, parents):
files_group = smb_parser.add_argument_group("File Operations")
files_group.add_argument("--put-file", action="append", nargs=2, metavar="FILE", help="Put a local file into remote target, ex: whoami.txt \\\\Windows\\\\Temp\\\\whoami.txt")
files_group.add_argument("--get-file", action="append", nargs=2, metavar="FILE", help="Get a remote file, ex: \\\\Windows\\\\Temp\\\\whoami.txt whoami.txt")
files_group.add_argument("--get-folder", action="append", nargs=2, metavar="DIR", help="Get a remote directory, ex: \\\\Windows\\\\Temp\\\\testing testing")
files_group.add_argument("--recursive", default=True, action=BooleanOptionalAction, help="Recursively get a folder")
files_group.add_argument("--ignore-empty-folders", default=False, action="store_true", help="Ignore empty folders when downloading")
files_group.add_argument("--append-host", action="store_true", help="append the host to the get-file filename")

cmd_exec_group = smb_parser.add_argument_group("Command Execution")
Expand Down
1 change: 1 addition & 0 deletions tests/e2e_commands.txt
Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,7 @@ netexec smb TARGET_HOST -u LOGIN_USERNAME -p LOGIN_PASSWORD KERBEROS -x ipconfig
netexec smb TARGET_HOST -u LOGIN_USERNAME -p LOGIN_PASSWORD KERBEROS --put-file TEST_NORMAL_FILE \\Windows\\Temp\\test_file.txt
netexec smb TARGET_HOST -u LOGIN_USERNAME -p LOGIN_PASSWORD KERBEROS --put-file TEST_NORMAL_FILE \\Windows\\Temp\\test_file.txt --put-file TEST_NORMAL_FILE \\Windows\\Temp\\test_file2.txt
netexec smb TARGET_HOST -u LOGIN_USERNAME -p LOGIN_PASSWORD KERBEROS --get-file \\Windows\\Temp\\test_file.txt /tmp/test_file.txt
netexec smb TARGET_HOST -u LOGIN_USERNAME -p LOGIN_PASSWORD KERBEROS --get-folder \\Windows\\Temp\\ /tmp/test_folder/
netexec smb TARGET_HOST -u LOGIN_USERNAME -p LOGIN_PASSWORD KERBEROS --no-admin-check
##### SMB PowerShell
netexec smb TARGET_HOST -u LOGIN_USERNAME -p LOGIN_PASSWORD KERBEROS -X ipconfig
Expand Down
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