PyCIRCLean/bin/filecheck.py

584 lines
22 KiB
Python

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import os
import mimetypes
import shlex
import subprocess
import time
import zipfile
import oletools.oleid
import olefile
import officedissector
import warnings
import exifread
from PIL import Image
# from PIL import PngImagePlugin
from pdfid import PDFiD, cPDFiD
from kittengroomer import FileBase, KittenGroomerBase, main
SEVENZ = '/usr/bin/7z'
# Prepare application/<subtype>
mimes_ooxml = ['vnd.openxmlformats-officedocument.']
mimes_office = ['msword', 'vnd.ms-']
mimes_libreoffice = ['vnd.oasis.opendocument']
mimes_rtf = ['rtf', 'richtext']
mimes_pdf = ['pdf', 'postscript']
mimes_xml = ['xml']
mimes_ms = ['dosexec']
mimes_compressed = ['zip', 'rar', 'bzip2', 'lzip', 'lzma', 'lzop',
'xz', 'compress', 'gzip', 'tar']
mimes_data = ['octet-stream']
# Prepare image/<subtype>
mimes_exif = ['image/jpeg', 'image/tiff']
mimes_png = ['image/png']
# Mime types we can pull metadata from
mimes_metadata = ['image/jpeg', 'image/tiff', 'image/png']
# Aliases
aliases = {
# Win executables
'application/x-msdos-program': 'application/x-dosexec',
'application/x-dosexec': 'application/x-msdos-program',
# Other apps with confusing mimetypes
'application/rtf': 'text/rtf',
}
# Sometimes, mimetypes.guess_type is giving unexpected results, such as for the .tar.gz files:
# In [12]: mimetypes.guess_type('toot.tar.gz', strict=False)
# Out[12]: ('application/x-tar', 'gzip')
# It works as expected if you do mimetypes.guess_type('application/gzip', strict=False)
propertype = {'.gz': 'application/gzip'}
# Commonly used malicious extensions
# Sources: http://www.howtogeek.com/137270/50-file-extensions-that-are-potentially-dangerous-on-windows/
# https://github.com/wiregit/wirecode/blob/master/components/core-settings/src/main/java/org/limewire/core/settings/FilterSettings.java
mal_ext = (
# Applications
".exe", ".pif", ".application", ".gadget", ".msi", ".msp", ".com", ".scr",
".hta", ".cpl", ".msc", ".jar",
# Scripts
".bat", ".cmd", ".vb", ".vbs", ".vbe", ".js", ".jse", ".ws", ".wsf",
".wsc", ".wsh", ".ps1", ".ps1xml", ".ps2", ".ps2xml", ".psc1", ".psc2",
".msh", ".msh1", ".msh2", ".mshxml", ".msh1xml", ".msh2xml",
# Shortcuts
".scf", ".lnk", ".inf",
# Other
".reg", ".dll",
# Office macro (OOXML with macro enabled)
".docm", ".dotm", ".xlsm", ".xltm", ".xlam", ".pptm", ".potm", ".ppam",
".ppsm", ".sldm",
# banned from wirecode
".asf", ".asx", ".au", ".htm", ".html", ".mht", ".vbs",
".wax", ".wm", ".wma", ".wmd", ".wmv", ".wmx", ".wmz", ".wvx",
)
class File(FileBase):
def __init__(self, src_path, dst_path):
''' Init file object, set the mimetype '''
super(File, self).__init__(src_path, dst_path)
self.is_recursive = False
if not self.has_mimetype():
# No mimetype, should not happen.
self.make_dangerous()
if not self.has_extension():
self.make_dangerous()
if self.extension in mal_ext:
self.log_details.update({'malicious_extension': self.extension})
self.make_dangerous()
if self.is_dangerous():
return
self.log_details.update({'maintype': self.main_type,
'subtype': self.sub_type,
'extension': self.extension})
# Check correlation known extension => actual mime type
if propertype.get(self.extension) is not None:
expected_mimetype = propertype.get(self.extension)
else:
expected_mimetype, encoding = mimetypes.guess_type(self.src_path, strict=False)
if aliases.get(expected_mimetype) is not None:
expected_mimetype = aliases.get(expected_mimetype)
is_known_extension = self.extension in mimetypes.types_map.keys()
if is_known_extension and expected_mimetype != self.mimetype:
self.log_details.update({'expected_mimetype': expected_mimetype})
self.make_dangerous()
# check correlation actual mime type => known extensions
if aliases.get(self.mimetype) is not None:
mimetype = aliases.get(self.mimetype)
else:
mimetype = self.mimetype
expected_extensions = mimetypes.guess_all_extensions(mimetype, strict=False)
if expected_extensions:
if len(self.extension) > 0 and self.extension not in expected_extensions:
self.log_details.update({'expected_extensions': expected_extensions})
self.make_dangerous()
else:
# there are no known extensions associated to this mimetype.
pass
def has_metadata(self):
if self.mimetype in mimes_metadata:
return True
return False
class KittenGroomerFileCheck(KittenGroomerBase):
def __init__(self, root_src=None, root_dst=None, max_recursive=2, debug=False):
'''
Initialize the basics of the conversion process
'''
if root_src is None:
root_src = os.path.join(os.sep, 'media', 'src')
if root_dst is None:
root_dst = os.path.join(os.sep, 'media', 'dst')
super(KittenGroomerFileCheck, self).__init__(root_src, root_dst, debug)
self.recursive = 0
self.max_recursive = max_recursive
subtypes_apps = [
(mimes_office, self._winoffice),
(mimes_ooxml, self._ooxml),
(mimes_rtf, self.text),
(mimes_libreoffice, self._libreoffice),
(mimes_pdf, self._pdf),
(mimes_xml, self.text),
(mimes_ms, self._executables),
(mimes_compressed, self._archive),
(mimes_data, self._binary_app),
]
self.subtypes_application = self._init_subtypes_application(subtypes_apps)
types_metadata = [
(mimes_exif, self._metadata_exif),
(mimes_png, self._metadata_png),
]
self.metadata_processing_options = self._init_subtypes_application(types_metadata)
self.mime_processing_options = {
'text': self.text,
'audio': self.audio,
'image': self.image,
'video': self.video,
'application': self.application,
'example': self.example,
'message': self.message,
'model': self.model,
'multipart': self.multipart,
'inode': self.inode,
}
# ##### Helpers #####
def _init_subtypes_application(self, subtypes_application):
'''
Create the Dict to pick the right function based on the sub mime type
'''
to_return = {}
for list_subtypes, fct in subtypes_application:
for st in list_subtypes:
to_return[st] = fct
return to_return
def _print_log(self):
'''
Print the logs related to the current file being processed
'''
tmp_log = self.log_name.fields(**self.cur_file.log_details)
if self.cur_file.is_dangerous():
tmp_log.warning(self.cur_file.log_string)
elif self.cur_file.log_details.get('unknown') or self.cur_file.log_details.get('binary'):
tmp_log.info(self.cur_file.log_string)
else:
tmp_log.debug(self.cur_file.log_string)
def _run_process(self, command_line, timeout=0, background=False):
'''Run subprocess, wait until it finishes'''
if timeout != 0:
deadline = time.time() + timeout
else:
deadline = None
args = shlex.split(command_line)
with open(self.log_debug_err, 'ab') as stderr, open(self.log_debug_out, 'ab') as stdout:
p = subprocess.Popen(args, stdout=stdout, stderr=stderr)
if background:
# This timer is here to make sure the unoconv listener is properly started.
time.sleep(10)
return True
while True:
code = p.poll()
if code is not None:
break
if deadline is not None and time.time() > deadline:
p.kill()
break
time.sleep(1)
return True
#######################
# ##### Discarded mime types, reason in the comments ######
def inode(self):
''' Usually empty file. No reason (?) to copy it on the dest key'''
if self.cur_file.is_symlink():
self.cur_file.log_string += 'Symlink to {}'.format(self.log_details['symlink'])
else:
self.cur_file.log_string += 'Inode file'
def unknown(self):
''' This main type is unknown, that should not happen '''
self.cur_file.log_string += 'Unknown file'
def example(self):
'''Used in examples, should never be returned by libmagic'''
self.cur_file.log_string += 'Example file'
def multipart(self):
'''Used in web apps, should never be returned by libmagic'''
self.cur_file.log_string += 'Multipart file'
# ##### Threated as malicious, no reason to have it on a USB key ######
def message(self):
'''Way to process message file'''
self.cur_file.log_string += 'Message file'
self.cur_file.make_dangerous()
self._safe_copy()
def model(self):
'''Way to process model file'''
self.cur_file.log_string += 'Model file'
self.cur_file.make_dangerous()
self._safe_copy()
# ##### Converted ######
def text(self):
for r in mimes_rtf:
if r in self.cur_file.sub_type:
self.cur_file.log_string += 'Rich Text file'
# TODO: need a way to convert it to plain text
self.cur_file.force_ext('.txt')
self._safe_copy()
return
for o in mimes_ooxml:
if o in self.cur_file.sub_type:
self.cur_file.log_string += 'OOXML File'
self._ooxml()
return
self.cur_file.log_string += 'Text file'
self.cur_file.force_ext('.txt')
self._safe_copy()
def application(self):
''' Everything can be there, using the subtype to decide '''
for subtype, fct in self.subtypes_application.items():
if subtype in self.cur_file.sub_type:
fct()
self.cur_file.log_string += 'Application file'
return
self.cur_file.log_string += 'Unknown Application file'
self._unknown_app()
def _executables(self):
'''Way to process executable file'''
self.cur_file.add_log_details('processing_type', 'executable')
self.cur_file.make_dangerous()
self._safe_copy()
def _winoffice(self):
self.cur_file.add_log_details('processing_type', 'WinOffice')
# Try as if it is a valid document
oid = oletools.oleid.OleID(self.cur_file.src_path)
if not olefile.isOleFile(self.cur_file.src_path):
# Manual processing, may already count as suspicious
try:
ole = olefile.OleFileIO(self.cur_file.src_path, raise_defects=olefile.DEFECT_INCORRECT)
except:
self.cur_file.add_log_details('not_parsable', True)
self.cur_file.make_dangerous()
if ole.parsing_issues:
self.cur_file.add_log_details('parsing_issues', True)
self.cur_file.make_dangerous()
else:
if ole.exists('macros/vba') or ole.exists('Macros') \
or ole.exists('_VBA_PROJECT_CUR') or ole.exists('VBA'):
self.cur_file.add_log_details('macro', True)
self.cur_file.make_dangerous()
else:
indicators = oid.check()
# Encrypted ban be set by multiple checks on the script
if oid.encrypted.value:
self.cur_file.add_log_details('encrypted', True)
self.cur_file.make_dangerous()
if oid.macros.value or oid.ole.exists('macros/vba') or oid.ole.exists('Macros') \
or oid.ole.exists('_VBA_PROJECT_CUR') or oid.ole.exists('VBA'):
self.cur_file.add_log_details('macro', True)
self.cur_file.make_dangerous()
for i in indicators:
if i.id == 'ObjectPool' and i.value:
# FIXME: Is it suspicious?
self.cur_file.add_log_details('objpool', True)
elif i.id == 'flash' and i.value:
self.cur_file.add_log_details('flash', True)
self.cur_file.make_dangerous()
self._safe_copy()
def _ooxml(self):
self.cur_file.add_log_details('processing_type', 'ooxml')
try:
doc = officedissector.doc.Document(self.cur_file.src_path)
except Exception:
# Invalid file
self.cur_file.make_dangerous()
self._safe_copy()
return
# There are probably other potentially malicious features:
# fonts, custom props, custom XML
if doc.is_macro_enabled or len(doc.features.macros) > 0:
self.cur_file.add_log_details('macro', True)
self.cur_file.make_dangerous()
if len(doc.features.embedded_controls) > 0:
self.cur_file.add_log_details('activex', True)
self.cur_file.make_dangerous()
if len(doc.features.embedded_objects) > 0:
# Exploited by CVE-2014-4114 (OLE)
self.cur_file.add_log_details('embedded_obj', True)
self.cur_file.make_dangerous()
if len(doc.features.embedded_packages) > 0:
self.cur_file.add_log_details('embedded_pack', True)
self.cur_file.make_dangerous()
self._safe_copy()
def _libreoffice(self):
self.cur_file.add_log_details('processing_type', 'libreoffice')
# As long as there ar no way to do a sanity check on the files => dangerous
try:
lodoc = zipfile.ZipFile(self.cur_file.src_path, 'r')
except:
self.cur_file.add_log_details('invalid', True)
self.cur_file.make_dangerous()
for f in lodoc.infolist():
fname = f.filename.lower()
if fname.startswith('script') or fname.startswith('basic') or \
fname.startswith('object') or fname.endswith('.bin'):
self.cur_file.add_log_details('macro', True)
self.cur_file.make_dangerous()
self._safe_copy()
def _pdf(self):
'''Way to process PDF file'''
self.cur_file.add_log_details('processing_type', 'pdf')
xmlDoc = PDFiD(self.cur_file.src_path)
oPDFiD = cPDFiD(xmlDoc, True)
# TODO: other keywords?
if oPDFiD.encrypt > 0:
self.cur_file.add_log_details('encrypted', True)
self.cur_file.make_dangerous()
if oPDFiD.js > 0 or oPDFiD.javascript > 0:
self.cur_file.add_log_details('javascript', True)
self.cur_file.make_dangerous()
if oPDFiD.aa > 0 or oPDFiD.openaction > 0:
self.cur_file.add_log_details('openaction', True)
self.cur_file.make_dangerous()
if oPDFiD.richmedia > 0:
self.cur_file.add_log_details('flash', True)
self.cur_file.make_dangerous()
if oPDFiD.launch > 0:
self.cur_file.add_log_details('launch', True)
self.cur_file.make_dangerous()
def _archive(self):
'''Way to process Archive'''
self.cur_file.add_log_details('processing_type', 'archive')
self.cur_file.is_recursive = True
self.cur_file.log_string += 'Archive extracted, processing content.'
tmpdir = self.cur_file.dst_path + '_temp'
self._safe_mkdir(tmpdir)
extract_command = '{} -p1 x "{}" -o"{}" -bd -aoa'.format(SEVENZ, self.cur_file.src_path, tmpdir)
self._run_process(extract_command)
self.recursive += 1
self.tree(tmpdir)
self.processdir(tmpdir, self.cur_file.dst_path)
self.recursive -= 1
self._safe_rmtree(tmpdir)
def _unknown_app(self):
'''Way to process an unknown file'''
self.cur_file.make_unknown()
self._safe_copy()
def _binary_app(self):
'''Way to process an unknown binary file'''
self.cur_file.make_binary()
self._safe_copy()
#######################
# Metadata extractors
def _metadata_exif(self, metadataFile):
img = open(self.cur_file.src_path, 'rb')
tags = None
try:
tags = exifread.process_file(img, debug=True)
except Exception as e:
print("Error while trying to grab full metadata for file {}; retrying for partial data.".format(self.cur_file.src_path))
print(e)
if tags is None:
try:
tags = exifread.process_file(img, debug=True)
except Exception as e:
print("Failed to get any metadata for file {}.".format(self.cur_file.src_path))
print(e)
img.close()
return False
for tag in sorted(tags.keys()):
# These are long and obnoxious/binary
if tag not in ('JPEGThumbnail', 'TIFFThumbnail'):
printable = str(tags[tag])
# Exifreader truncates data.
if len(printable) > 25 and printable.endswith(", ... ]"):
value = tags[tag].values
if isinstance(value, basestring):
printable = value
else:
printable = str(value)
metadataFile.write("Key: {}\tValue: {}\n".format(tag, printable))
self.cur_file.add_log_details('metadata', 'exif')
img.close()
return True
def _metadata_png(self, metadataFile):
warnings.simplefilter('error', Image.DecompressionBombWarning)
try:
img = Image.open(self.cur_file.src_path)
for tag in sorted(img.info.keys()):
# These are long and obnoxious/binary
if tag not in ('icc_profile'):
metadataFile.write("Key: {}\tValue: {}\n".format(tag, img.info[tag]))
self.cur_file.add_log_details('metadata', 'png')
img.close()
# Catch decompression bombs
except Exception as e:
print("Caught exception processing metadata for {}".format(self.cur_file.src_path))
print(e)
self.cur_file.make_dangerous()
self._safe_copy()
return False
def extract_metadata(self):
metadataFile = self._safe_metadata_split(".metadata.txt")
success = self.metadata_processing_options.get(self.cur_file.mimetype)(metadataFile)
metadataFile.close()
if not success:
# FIXME Delete empty metadata file
pass
#######################
# ##### Not converted, checking the mime type ######
def audio(self):
'''Way to process an audio file'''
self.cur_file.log_string += 'Audio file'
self._media_processing()
def image(self):
'''Way to process an image'''
if self.cur_file.has_metadata():
self.extract_metadata()
# FIXME make sure this works for png, gif, tiff
# Create a temp directory
dst_dir, filename = os.path.split(self.cur_file.dst_path)
tmpdir = os.path.join(dst_dir, 'temp')
tmppath = os.path.join(tmpdir, filename)
self._safe_mkdir(tmpdir)
# Do our image conversions
warnings.simplefilter('error', Image.DecompressionBombWarning)
try:
imIn = Image.open(self.cur_file.src_path)
imOut = Image.frombytes(imIn.mode, imIn.size, imIn.tobytes())
imOut.save(tmppath)
# Copy the file back out and cleanup
self._safe_copy(tmppath)
self._safe_rmtree(tmpdir)
# Catch decompression bombs
except Exception as e:
print("Caught exception (possible decompression bomb?) while translating file {}.".format(self.cur_file.src_path))
print(e)
self.cur_file.make_dangerous()
self._safe_copy()
self.cur_file.log_string += 'Image file'
self.cur_file.add_log_details('processing_type', 'image')
def video(self):
'''Way to process a video'''
self.cur_file.log_string += 'Video file'
self._media_processing()
def _media_processing(self):
'''Generic way to process all the media files'''
self.cur_file.add_log_details('processing_type', 'media')
self._safe_copy()
#######################
def processdir(self, src_dir=None, dst_dir=None):
'''
Main function doing the processing
'''
if src_dir is None:
src_dir = self.src_root_dir
if dst_dir is None:
dst_dir = self.dst_root_dir
if self.recursive > 0:
self._print_log()
if self.recursive >= self.max_recursive:
self.cur_file.make_dangerous()
self.cur_file.add_log_details('Archive Bomb', True)
self.log_name.warning('ARCHIVE BOMB.')
self.log_name.warning('The content of the archive contains recursively other archives.')
self.log_name.warning('This is a bad sign so the archive is not extracted to the destination key.')
self._safe_rmtree(src_dir)
if src_dir.endswith('_temp'):
archbomb_path = src_dir[:-len('_temp')]
self._safe_remove(archbomb_path)
for srcpath in self._list_all_files(src_dir):
self.cur_file = File(srcpath, srcpath.replace(src_dir, dst_dir))
self.log_name.info('Processing {} ({}/{})', srcpath.replace(src_dir + '/', ''),
self.cur_file.main_type, self.cur_file.sub_type)
if not self.cur_file.is_dangerous():
self.mime_processing_options.get(self.cur_file.main_type, self.unknown)()
else:
self._safe_copy()
if not self.cur_file.is_recursive:
self._print_log()
if __name__ == '__main__':
main(KittenGroomerFileCheck, 'Generic version of the KittenGroomer. Convert and rename files.')