CVE-2022-36760: Inconsistent Interpretation of HTTP Requests in Apache HTTP Server mod_proxy_ajp Vulnerability Analysis

The CVE-2022-36760 vulnerability is a dangerous security flaw in the popular Apache HTTP Server software, specifically in the mod_proxy_ajp module. This vulnerability, dubbed "HTTP Request Smuggling," allows a malicious attacker to smuggle requests to the AJP server the affected Apache server forwards requests to. In this long-read post, we will dive into the details of this vulnerability – including a code snippet, links to original references, and a brief explanation of how the exploit works.

Affected Products

The CVE-2022-36760 vulnerability affects Apache HTTP Server version 2.4.54 and prior versions.

Vulnerability Details

HTTP Request Smuggling is a type of web security vulnerability that impacts the way HTTP requests are processed by web servers and proxies. In the context of this specific vulnerability, the issue arises due to an inconsistent interpretation of HTTP requests when using the mod_proxy_ajp module in Apache HTTP Server.

Exploit Details

The CVE-2022-36760 vulnerability can be exploited by an attacker sending a specially crafted HTTP request to the Apache HTTP Server. This crafted request takes advantage of the inconsistent interpretation of HTTP requests, allowing the attacker to manipulate the data being sent to the AJP server. By doing this, an attacker can effectively smuggle requests to the AJP server, potentially opening up unauthorized access and the possibility of further attacks.

Code Snippet

To better understand the vulnerability, let's take a look at a simple code snippet demonstrating the issue. The mod_proxy_ajp module in Apache HTTP server parses incoming HTTP requests and forwards them to an AJP server. Let's assume this fictional code snippet representing the vulnerable portion of the mod_proxy_ajp module:

function process_request(request) {
  // Parse the HTTP request
  ...
  var proxy_ajp = new Proxy_AJP(...)
  // Forward the request to the AJP server
  proxy_ajp.forward_request(request)
}

In this scenario, the process_request function doesn't properly handle inconsistencies in the incoming HTTP request. As a result, a malicious attacker could carefully craft an HTTP request in such a way that it causes unintended behavior when interpreted and forwarded by the mod_proxy_ajp module.

Original References

Official CVE Database: https://nvd.nist.gov/vuln/detail/CVE-2022-36760
Apache HTTP Server Announcement: https://www.apache.org/security/asf-httpoxy-response.txt

Mitigation and Recommendations

To remediate the CVE-2022-36760 vulnerability, it is highly recommended to apply the security updates provided by the Apache HTTP Server project. Ensure that the mod_proxy_ajp module has been updated to a fixed version, so that the inconsistency in the interpretation of HTTP requests no longer exists.

In addition to applying the security updates, the following protective measures are recommended

1. Monitor your Apache HTTP Server logs for suspicious activity that could indicate attempted exploitation of this vulnerability.
2. Restrict access to sensitive AJP server resources and implement strict firewall rules to limit inbound and outbound traffic.
3. Regularly review and update your web server and proxy configurations to ensure they provide the appropriate level of security.

Conclusion

The CVE-2022-36760 vulnerability poses a serious risk to Apache HTTP Server installations, allowing attackers to smuggle requests to the AJP server by exploiting an inconsistent interpretation of HTTP requests in the mod_proxy_ajp module. By understanding the exploit details, code snippet, and original references, system administrators and security professionals are better equipped to secure their Apache HTTP Server installations against this dangerous vulnerability.

Timeline

Published on: 01/17/2023 20:15:00 UTC
Last modified on: 01/30/2023 19:21:00 UTC