Apache Httpd 2.4.18 Exploit

The Hunt for Apache httpd 2.4.18 Exploits: A Retrospective on Vulnerabilities, Failures, and Mitigations

Introduction

In the world of web server security, version numbers often become shorthand for critical vulnerabilities. For system administrators and penetration testers, Apache HTTP Server 2.4.18 holds a particular, albeit complex, place in the collective memory. Released in December 2015, this version was the standard on several long-term support (LTS) Linux distributions, most notably Ubuntu 16.04 LTS (Xenial Xerus).

: Detailed technical walkthroughs and proof-of-concept code are available at Exploit-DB (EDB-ID: 46676) Exploit-DB Secondary Vulnerabilities Other risks associated with this version include: X.509 Authentication Bypass (CVE-2016-4979) : Affects the experimental HTTP/2 module (

GET /admin/delete?user=admin HTTP/1.1 Host: vulnerable-website.com Foo: x apache httpd 2.4.18 exploit

For 2.4.18 specifically, request smuggling is less relevant because the patches for mod_proxy came later.

. However, sticking with this version today poses significant security risks. If you are still running 2.4.18, you are exposed to several well-documented vulnerabilities that can lead to everything from information leaks to full server compromise. Key Vulnerabilities in Apache 2.4.18 The Hunt for Apache httpd 2

As he dug deeper, John discovered that the server was running Apache httpd version 2.4.18, an outdated version that was vulnerable to a known exploit. The alert indicated that someone had been attempting to exploit the vulnerability, trying to gain unauthorized access to the server.

2. Version Context

| Attribute | Value | |-----------|-------| | Release Date | December 2015 | | HTTP/2 Support | Experimental (known bugs) | | End-of-Life Status | Officially EOL as of 2017 (unsupported) | | Common Distributions | Ubuntu 16.04 LTS (Xenial), Debian 9 (Stretch), RHEL 7.x (backported patches) | For 2.4.18 specifically

The Ethical Exploit Roadmap

For educational purposes, an ethical hacker targeting a lab environment with Apache 2.4.18 would follow this roadmap:

  1. Recon: nmap -sV -p80 --script http-apache-negotiation <target>
  2. Banner grab confirms Server: Apache/2.4.18
  3. Run HTTPOXY scanner:
    python3 httpoxy_scanner.py --url http://target/cgi-bin/test.cgi
  4. If CGI enabled:
    Redirect request to attacker proxy → capture backend API keys.
  5. Otherwise: Launch Optionsbleed:
    curl -X OPTIONS http://target/ -H "Limit: 0" → leak memory.