Added findSymbols.py

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Mariusz B. / mgeeky 2021-10-22 20:14:09 +02:00
parent 8589f46e55
commit 2051159996

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#!/usr/bin/python3
#
# A script that enumerates Imports and Exports of PE files and prints them according to search criterias.
#
# Let's the user find modules matching criterias such as:
# - modules that are .NET ones
# - modules of a big enough size / SizeOfImage / code section size
# - modules with enough room to fit shellcode for Module Stomping/DLL Hollowing purposes
# (calculated as a difference of upper code section address and an entry point address)
# - modules present at the same time in System32 and SysWOW64
# - modules used / not used by any process as examined during the scan
#
# Mariusz B. / mgeeky, '21
# <mb [at] binary-offensive.com>
#
import os
import re
import sys
import glob
import json
import time
import signal
import pprint
import pefile
import tabulate
import platform
import textwrap
import argparse
import tempfile
import subprocess
import multiprocessing
from datetime import datetime
from itertools import product
from multiprocessing import Pool, Queue, Process, freeze_support, Manager, Lock
DEFAULT_COLUMN_SORTED = 'symbol'
headers = [
'filename',
'symbol type',
'module',
'symbol',
'file size',
'path',
]
symbol_idx = headers.index('symbol')
def out(x):
sys.stderr.write(x + '\n')
def verbose(args, x):
if args.verbose:
sys.stderr.write('[verbose] ' + x + '\n')
def collectImports(args, mod):
imports = []
if not hasattr(mod, 'DIRECTORY_ENTRY_IMPORT') or not mod.DIRECTORY_ENTRY_IMPORT:
return imports
try:
for entry in mod.DIRECTORY_ENTRY_IMPORT:
module = entry.dll.decode('utf-8').lower()
for func in entry.imports:
if not func.name:
continue
func = func.name.decode()
imports.append(('import', module, func))
except Exception as e:
verbose(args, f'Exception occured while collecting PE imports: {e}')
return imports
def collectExports(args, filename, mod):
exports = []
if not hasattr(mod, 'DIRECTORY_ENTRY_EXPORT') or not mod.DIRECTORY_ENTRY_EXPORT:
return exports
try:
for entry in mod.DIRECTORY_ENTRY_EXPORT.symbols:
if not entry.name:
continue
func = entry.name.decode()
exports.append(('export', os.path.basename(filename), func))
except Exception as e:
verbose(args, f'Exception occured while collecting PE exports: {e}')
return exports
def verifyCriterias(args, regexes, infos, uniqueSymbols):
if args.unique and infos['symbol'] in uniqueSymbols:
verbose(args, f'(-) Skipping symbol {infos["module"]}.{infos["symbol"]} because it is not unique in our results.')
return False
if args.imports and infos['symbol type'] != 'import':
verbose(args, f'(-) Skipping symbol {infos["module"]}.{infos["symbol"]} because it was not an import.')
return False
if args.exports and infos['symbol type'] != 'export':
verbose(args, f'(-) Skipping symbol {infos["module"]}.{infos["symbol"]} because it was not an export.')
return False
regexesVerified = sum([len(v) for k, v in regexes.items()])
for rex in regexes['not-name']:
match = rex.search(infos['symbol'])
if match:
verbose(args, f'(-) Skipping symbol {infos["module"]}.{infos["symbol"]} as it DID satisfy not-name regex.')
return False
for rex in regexes['not-module']:
match = rex.search(infos['module'])
if match:
verbose(args, f'(-) Skipping symbol\'s module {infos["module"]}.{infos["symbol"]} as it DID satisfy not-module regex.')
return False
satisifed = False
carryOn = False
if len(regexes['module']) > 0:
for rex in regexes['module']:
match = rex.search(infos['module'])
if match:
verbose(args, f'(+) Symbol\'s module {infos["module"]}.{infos["symbol"]} satisfied module regex.')
carryOn = True
break
else:
carryOn = True
if carryOn:
for rex in regexes['name']:
match = rex.search(infos['symbol'])
if match:
verbose(args, f'(+) Symbol {infos["module"]}.{infos["symbol"]} satisfied name regex.')
satisifed = True
break
if regexesVerified == 0 or satisifed:
verbose(args, f'(+) Symbol {infos["module"]}.{infos["symbol"]} satisfied all criterias.')
return True
else:
verbose(args, f'(-) Skipping symbol {infos["module"]}.{infos["symbol"]} as it DID NOT satisfy all criterias.')
return False
def processFileWorker(arguments):
out = None
try:
(args, regexes, path, results, uniqueSymbols, filesProcessed, symbolsProcessed) = arguments
out = processFile(args, regexes, path, results, uniqueSymbols, filesProcessed, symbolsProcessed)
except (KeyboardInterrupt, SystemExit) as e:
out(e)
return out
def processFile(args, regexes, path, results, uniqueSymbols, filesProcessed, symbolsProcessed):
verbose(args, 'Processing file: ' + path)
mod = None
try:
mod = pefile.PE(path, fast_load = True)
mod.parse_data_directories()
except:
return
imports = collectImports(args, mod)
exports = collectExports(args, os.path.basename(path), mod)
symbols = imports + exports
mod.close()
once = False
for (symbolType, symbolModule, symbolName) in symbols:
infos = {
'path' : path,
'filename' : os.path.basename(path),
'file size' : os.path.getsize(path),
'symbol type' : symbolType,
'symbol' : symbolName,
'module' : symbolModule,
}
if not once:
assert len(infos.keys()) == len(headers), "headers and infos.keys() mismatch"
assert list(infos.keys()).sort() == list(headers).sort(), "headers and infos.keys() mismatch while sorted"
once = True
if args.format == 'text':
appendRow = verifyCriterias(args, regexes, infos, uniqueSymbols)
if appendRow:
row = []
MaxWidth = 80
for h in headers:
obj = None
if type(infos[h]) == set or type(infos[h]) == list or type(infos[h]) == tuple:
obj = ', '.join(infos[h])
else:
obj = infos[h]
if type(obj) == str and len(obj) > MaxWidth:
obj = '\n'.join(textwrap.wrap(obj, width = MaxWidth))
row.append(obj)
results.append(row)
uniqueSymbols.append(symbolName)
#verbose(args, 'Processed results:\n' + pprint.pformat(infos))
else:
verbose(args, f'Symbol {symbolModule}.{symbolName} did not met filter criterias.')
elif args.format == 'json':
appendRow = verifyCriterias(args, regexes, infos, uniqueSymbols)
if appendRow:
results.append(row)
uniqueSymbols.append(symbolName)
#verbose(args, 'Processed results:\n' + pprint.pformat(infos))
else:
verbose(args, f'Symbol {symbolModule}.{symbolName} did not met filter criterias.')
filesProcessed.value += 1
symbolsProcessed.value += len(symbols)
def trap_handler(signum, frame):
out('[-] CTRL-C pressed. Wait a minute until all processes wrap up.')
def init_worker():
signal.signal(signal.SIGINT, trap_handler)
def processDir(args, regexes, path, results, uniqueSymbols, filesProcessed, symbolsProcessed):
filePaths = []
for file in glob.glob(os.path.join(path, '**'), recursive=args.recurse):
if os.path.isfile(file):
looks_like_pe = False
with open(file, 'rb') as f:
mz = f.read(2)
if len(mz) == 2:
looks_like_pe = (mz[0] == ord('M') and mz[1] == ord('Z')) or (mz[1] == ord('M') and mz[0] == ord('Z'))
if looks_like_pe: filePaths.append(file)
cpu_count = multiprocessing.cpu_count()
pool = Pool(cpu_count, initializer=init_worker)
try:
arguments = [[args, regexes, _path, results, uniqueSymbols, filesProcessed, symbolsProcessed] for _path in filePaths]
out(f'[.] Will scan {len(filePaths)} files...')
res = pool.map(processFileWorker, arguments)
except KeyboardInterrupt:
out(f'[-] User interrupted the scan after {filesProcessed.value} files.')
pool.terminate()
pool.join()
def opts(argv):
params = argparse.ArgumentParser(
prog = argv[0],
usage='%(prog)s [options] <path>'
)
params.add_argument('path', help = 'Path to a PE file or directory.')
params.add_argument('-r', '--recurse', action='store_true', help='If <path> is a directory, perform recursive scan.')
params.add_argument('-v', '--verbose', action='store_true', help='Verbose mode.')
params.add_argument('-f', '--format', choices=['text', 'json'], default='text', help='Output format. Text or JSON.')
sorting = params.add_argument_group('Output sorting')
sorting.add_argument('-u', '--unique', action='store_true', help = 'Return unique symbols only. The first symbol with a name that occurs in results, will be returned.')
sorting.add_argument('-d', '--descending', action='store_true', help = 'Sort in descending order instead of default of descending.')
sorting.add_argument('-c', '--column', default=DEFAULT_COLUMN_SORTED, choices=headers, metavar='COLUMN', help = 'Sort by this column name. Default: filename. Available columns: "' + '", "'.join(headers) + '"')
sorting.add_argument('-n', '--first', type=int, default=0, metavar='NUM', help='Show only first N results, as specified in this paremeter. By default will show all candidates.')
filters = params.add_argument_group('Output filtering')
sorting.add_argument('-i', '--imports', action='store_true', help = 'Filter only Imports.')
sorting.add_argument('-e', '--exports', action='store_true', help = 'Filter only Exports.')
filters.add_argument('-s', '--name', action='append', default=[], help = 'Search for symbols with name matching this regular expression. Can be repeated, case insensitive, constructs: ".+VALUE.+"')
filters.add_argument('-S', '--not-name', action='append', default=[], help = 'Search for symbols with name NOT matching this regular expression.')
filters.add_argument('-m', '--module', action='append', default=[], help = 'Search for symbols exported in/imported from this module matching regular expression.')
filters.add_argument('-M', '--not-module', action='append', default=[], help = 'Search for symbols NOT exported in/NOT imported from this module matching regular expression.')
args = params.parse_args()
if args.imports and args.exports:
out('[!] --imports and --exports are mutually exclusive. Pick only one of them!')
sys.exit(1)
accomodate_rex = lambda x: x
regexes = {
'name': [],
'not-name': [],
'module': [],
'not-module': []
}
for name in args.name:
regexes['name'].append(re.compile(accomodate_rex(name), re.I))
for not_name in args.not_name:
regexes['not-name'].append(re.compile(accomodate_rex(not_name), re.I))
for module in args.module:
regexes['module'].append(re.compile(accomodate_rex(module), re.I))
for not_module in args.not_module:
regexes['not-module'].append(re.compile(accomodate_rex(not_module), re.I))
return args, regexes
def main():
results = Manager().list()
uniqueSymbols = Manager().list()
filesProcessed = Manager().Value('i', 0)
symbolsProcessed = Manager().Value('i', 0)
out('''
:: scanSymbols.py - Searches PE Import/Exports based on supplied conditions.
Mariusz B. / mgeeky, '21
<mb [at] binary-offensive.com>
''')
args, regexes = opts(sys.argv)
is_wow64 = (platform.architecture()[0] == '32bit' and 'ProgramFiles(x86)' in os.environ)
start_time = datetime.now()
try:
if '\\system32\\' in args.path.lower() and is_wow64:
verbose(args, 'Redirecting input path from System32 to SysNative as we run from 32bit Python.')
args.path = args.path.lower().replace('\\system32\\', '\\SysNative\\')
if os.path.isdir(args.path):
processDir(args, regexes, args.path, results, uniqueSymbols, filesProcessed, symbolsProcessed)
else:
if not os.path.isfile(args.path):
out(f'[!] Input file does not exist! Path: {args.path}')
sys.exit(1)
processFile(args, regexes, args.path, results, uniqueSymbols, filesProcessed, symbolsProcessed)
except KeyboardInterrupt:
out(f'[-] User interrupted the scan.')
time_elapsed = datetime.now() - start_time
if args.format == 'json':
resultsList = list(results)
print(json.dumps(resultsList, indent=4))
else:
resultsList = list(results)
if len(resultsList) > 0:
idx = headers.index(args.column)
resultsList.sort(key = lambda x: x[idx], reverse = args.descending)
headers[idx] = '' + headers[idx] if args.descending else '' + headers[idx]
if args.first > 0:
for i in range(len(resultsList) - args.first):
resultsList.pop()
table = tabulate.tabulate(resultsList, headers=['#',] + headers, showindex='always', tablefmt='pretty')
print(table)
if args.first > 0:
out(f'\n[+] Found {len(resultsList)} symbols meeting all the criterias (but shown only first {args.first} ones).\n')
else:
out(f'\n[+] Found {len(resultsList)} symbols meeting all the criterias.\n')
else:
out(f'[-] Did not find symbols meeting specified criterias.')
out(f'[.] Processed {filesProcessed.value} files and {symbolsProcessed.value} symbols.')
out('[.] Time elapsed: {}'.format(time_elapsed))
if __name__ == '__main__':
freeze_support()
main()