Skip to content

Instantly share code, notes, and snippets.

@zuphzuph zuphzuph/checksvc.py forked from wdormann/checksvc.py
Created Oct 19, 2018

Embed
What would you like to do?
Check for insecure services on Windows
import os
import subprocess
import ctypes
# See: https://blogs.msmvps.com/erikr/2007/09/26/set-permissions-on-a-specific-service-windows/
svcinfo = {}
nonadmin = ['AU', 'AN', 'BG', 'BU', 'DG', 'WD', 'IU', 'LG']
FNULL = open(os.devnull, 'w')
def checkadmin():
return ctypes.windll.shell32.IsUserAnAdmin()
def sliceperms(permstring):
permparts = []
if permstring:
parts = int(len(permstring))
# print('%s parts' % parts)
for i in range(0, parts, 2):
# print(permstring[i:i+2])
permparts.append(permstring[i:i + 2])
return permparts
def getsvcacls(svcname):
svcacl = None
try:
svcacl = subprocess.check_output(['sc', 'sdshow', svcname], stderr=FNULL).decode('utf-8',
'backslashreplace').strip()
except subprocess.CalledProcessError:
pass
return svcacl
def checkuserstartable(svcacl):
userstartable = False
if svcacl:
acllist = svcacl.split(')')
for acl in acllist:
if acl:
if acl.startswith('D:'):
acl = acl.replace('D:', '')
acl = acl.replace('(', '')
aclparts = acl.split(';')
usercode = aclparts[-1]
if usercode in nonadmin:
perms = aclparts[2]
# print('we have permissions for non-admin(%s): %s' % (usercode, perms))
permparts = sliceperms(perms)
# print('%s: %s' % (usercode, permparts))
if 'RP' in permparts:
# print('**** This can be started by a non-admin! ****')
userstartable = True
return userstartable
def checkuserstoppable(svcacl):
userstoppable = False
if svcacl:
acllist = svcacl.split(')')
for acl in acllist:
if acl:
if acl.startswith('D:'):
acl = acl.replace('D:', '')
acl = acl.replace('(', '')
aclparts = acl.split(';')
usercode = aclparts[-1]
if usercode in nonadmin:
perms = aclparts[2]
# print('we have permissions for non-admin(%s): %s' % (usercode, perms))
permparts = sliceperms(perms)
# print('%s: %s' % (usercode, permparts))
if 'WP' in permparts:
# print('**** This can be started by a non-admin! ****')
userstoppable = True
return userstoppable
def checkpathacl(path):
issues = []
if path:
try:
with open(path, 'wb') as f:
issues.append('WRITABLE SERVICE HOST')
except IOError:
pass
path = os.path.join(os.path.dirname(path), 'acltest')
if os.path.exists(path):
path = path + '1'
try:
with open(path, 'wb') as f:
issues.append('WRITABLE SERVICE HOST DIRECTORY')
os.unlink(path)
except IOError:
pass
return ', '.join(issues)
def whichfile(file):
if file:
fullpath = ''
try:
fullpath = subprocess.check_output(['where', file, ], stderr=FNULL).decode('utf-8',
'backslashreplace').strip()
except subprocess.CalledProcessError:
pass
return fullpath
def svchosttarget(svcname):
parsed = ''
svctarget = ''
try:
parsed = subprocess.check_output(['reg', 'query',
r'HKLM\SYSTEM\CurrentControlSet\Services\%s\Parameters' %
svcname], stderr=FNULL).decode('utf-8', 'backslashreplace')
except subprocess.CalledProcessError:
pass
for line in parsed.splitlines():
if ' servicedll ' in line.lower():
lineparts = line.split(' REG_EXPAND_SZ ')
svctarget = os.path.expandvars((lineparts[-1]))
if not os.path.exists(svctarget):
svctarget = whichfile(svctarget)
return svctarget
def checkservices():
nameindex = None
dispnameindex = None
privindex = None
stateindex = None
pathindex = None
startmodeindex = None
parsed = subprocess.check_output(['wmic', 'service', 'get', 'name,startname,displayname,state,pathname,startmode,'
'DesktopInteract',
'/format:csv'], stderr=FNULL).decode(
'utf-8', 'backslashreplace')
for line in parsed.splitlines():
if line:
columns = line.split(',')
if line.startswith('Node,'):
nameindex = columns.index('Name')
dispnameindex = columns.index('DisplayName')
privindex = columns.index('StartName')
stateindex = columns.index('State')
pathindex = columns.index('PathName')
startmodeindex = columns.index('StartMode')
desktopindex = columns.index('DesktopInteract')
else:
reasons = []
svcname = columns[nameindex]
svcdict = {}
svcdict['priv'] = columns[privindex]
svcdict['dispname'] = columns[dispnameindex]
svcdict['state'] = columns[stateindex]
svcdict['path'] = columns[pathindex]
svcdict['startmode'] = columns[startmodeindex]
svcdict['desktop'] = columns[desktopindex]
if svcdict['desktop'].lower() == 'true':
svcdict['desktop'] = True
else:
svcdict['desktop'] = False
if 'svchost.exe' in svcdict['path']:
realtarget = svchosttarget(svcname)
if realtarget:
# print('%s uses svchost: %s' % (svcname,realtarget))
svcdict['path'] = realtarget
elif '"' in svcdict['path']:
# Quoted path
splitpath = svcdict['path'].split('"')
if len(splitpath) > 2 and splitpath[2]:
# Quoted path with arguments
svcdict['path'] = '"%s"' % splitpath[1]
else:
# Quoted path without arguments
pass
else:
# Non-quoted path
splitpath = svcdict['path'].split()
if len(splitpath) > 1:
# Non-quoted path with arguments
svcdict['path'] = splitpath[0]
svcacls = getsvcacls(svcname)
startable = checkuserstartable(svcacls)
stoppable = checkuserstoppable(svcacls)
svcdict['startable'] = False
if startable and svcdict['startmode'] != 'Disabled':
if svcdict['state'] == 'Stopped' or (svcdict['state'] == 'Running' and stoppable):
svcdict['startable'] = True
svcinfo[svcname] = svcdict
badacls = checkpathacl(svcinfo[svcname]['path'])
if badacls:
reasons.append('Filesystem ACLs')
if (svcdict['startable'] and svcdict['priv'].lower() == 'localsystem') and not svcdict[
'path'].endswith('lsass.exe') and svcdict['path'].lower().replace('"', '').endswith('.exe'):
reasons.append('User-controlled and high-privileged')
if svcdict['desktop'] and svcdict['priv'].lower() == 'localsystem' and (svcdict['state'].lower() == \
'running' or svcdict['startable']):
reasons.append('Desktop interactive')
reasons = ', '.join(reasons)
if reasons:
if badacls:
print('%s !!!! %s is vulnerable (%s) !!!!' % (os.linesep, svcname, reasons))
else:
print('%s -=-= %s MAY be vulnerable (%s) =-=-' % (os.linesep, svcname, reasons))
print('Service: %s' % svcname)
print('Display name: %s' % svcinfo[svcname]['dispname'])
print('Privilege: %s' % svcinfo[svcname]['priv'])
print('Path: %s' % svcinfo[svcname]['path'])
print('State: %s' % svcinfo[svcname]['state'])
print('User-startable: %s' % svcinfo[svcname]['startable'])
print('Can interact with desktop: %s' % svcinfo[svcname]['desktop'])
if badacls:
print('ACL Problem(s): %s' % badacls)
if __name__ == "__main__":
if checkadmin():
print('Please run this script without administrative privileges.')
else:
checkservices()
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.