This specific payload style is seen in the wild from:
At first glance, the string -include-..-2F..-2F..-2F..-2Froot-2F looks like gibberish. To a security professional, it is a recognizable pattern of URL encoding and directory traversal mixed with application logic.
This payload attempts to perform two actions simultaneously:
The -2F sequences are URL-encoded representations of the forward slash (/). The .. represents the parent directory. Put together: ..-2F..-2F..-2F..-2Froot-2F decodes to ../../../../root/.
Properly handling file paths in web applications is crucial for security. By normalizing paths, validating user input, and restricting access to intended directories, developers can significantly reduce the risk of path traversal and other file system-related attacks. Always stay informed about potential security threats and follow best practices to secure your applications.
The string -include-..-2F..-2F..-2F..-2Froot-2F is a classic payload used to exploit a Path Traversal (or Directory Traversal) vulnerability in web applications. What the Payload Does
This payload attempts to "climb" out of the application's intended directory to access the system's root folder. : Often refers to a function (like in PHP) that dynamically loads files based on user input. : This is a URL-encoded version of . In a file system, means "go up one directory level". : The goal is to reach the root directory ( ) or a specific sensitive folder like to read protected system files. How the Attack Works Path Traversal | OWASP Foundation
Security Write-up: Local File Inclusion (LFI) via Path Traversal This write-up analyzes a Local File Inclusion (LFI)
vulnerability using directory traversal sequences. The specific payload provided, -include-..-2F..-2F..-2F..-2Froot-2F
, indicates an attempt to escape the application's intended directory to access the system's root folder. 1. Vulnerability Overview Vulnerability Type: Path Traversal / Directory Traversal Common Weakness Enumeration: -include-..-2F..-2F..-2F..-2Froot-2F
: Improper Limitation of a Pathname to a Restricted Directory Description:
This flaw occurs when an application uses user-supplied input to construct a file path without proper validation. Attackers use special sequences (like
) to navigate out of the web root and access restricted sensitive files on the server. 2. Payload Analysis The payload ..-2F..-2F..-2F..-2Froot-2F breaks down as follows:
: The "dot-dot" sequence instructs the operating system to move up one level in the directory hierarchy.
: This is a URL-encoded representation of the forward slash (
). Attackers often use encoding to bypass basic security filters that only look for literal characters.
: The target destination, aiming for the system's root directory ( ) or a specific folder named at the base of the file system. 3. Technical Impact A successful exploit can lead to: Path Traversal - Web Security Academy - PortSwigger
The keyword sequence "-include-..-2F..-2F..-2F..-2Froot-2F" is not a standard literary phrase, but rather a representation of a Path Traversal or Directory Traversal attack string. Specifically, it uses URL-encoded characters (-2F representing /) to attempt to "escape" a web application's intended directory and access restricted system files—in this case, the root directory.
Understanding this keyword is vital for developers and cybersecurity professionals looking to harden their systems against unauthorized access. The Anatomy of a Path Traversal Attack This specific payload style is seen in the
Path traversal (also known as "dot-dot-slash" attacks) targets vulnerabilities in web applications that use user-supplied input to construct file paths. When an application doesn't properly sanitize this input, an attacker can use the ../ sequence to navigate upward through the server's file system. In the keyword provided:
-include-: Suggests a function in a programming language (like PHP’s include()) that is being targeted.
..-2F: This is the URL-encoded version of ../. By repeating this sequence, the attacker moves up several levels.
root-2F: This represents /root/, the home directory for the system administrator (root user) on Linux-based systems. Why This Vulnerability Exists
Web applications often need to load dynamic content, such as images or localized text files. For example, a URL might look like this:https://example.com
If the back-end code takes that page parameter and plugs it directly into a file system call without checking it, an attacker can swap contact.html with our keyword string. The server might then attempt to "include" a sensitive system file, such as /etc/passwd, and display its contents to the attacker. The Risks of Improper File Handling A successful traversal attack can lead to:
Information Disclosure: Attackers can read sensitive configuration files, database credentials, and system passwords.
Remote Code Execution (RCE): If an attacker can "include" a file they have previously uploaded (like a log file containing malicious scripts), they may execute code on the server.
Full System Compromise: Accessing the root directory is often the final step in taking total control of a web server. How to Prevent Path Traversal The -2F sequences are URL-encoded representations of the
Securing an application against strings like ..-2F..-2F requires a multi-layered defense strategy:
Input Validation: Never trust user input. Use a "whitelist" approach—only allow specific, known-good characters (like alphanumeric characters) and reject anything containing dots or slashes.
Use Built-in Functions: Instead of building paths manually, use filesystem APIs that resolve paths and ensure they remain within a specific "base" directory (e.g., realpath() in PHP or path.resolve() in Node.js).
Filesystem Permissions: Run the web server with the "least privilege" necessary. A web server should never have permission to read the /root/ directory or sensitive system files.
Web Application Firewalls (WAF): Modern WAFs are designed to detect and block common attack patterns, including URL-encoded traversal sequences like -2F..-2F. Conclusion
The string "-include-..-2F..-2F..-2F..-2Froot-2F" serves as a stark reminder of the importance of secure coding practices. While it may look like gibberish to the untrained eye, it represents a direct attempt to bypass security boundaries. By understanding how these attacks work, developers can build more resilient applications and protect sensitive data from exposure.
To prevent directory traversal attacks:
In the context of web security, paths like this are often associated with directory traversal attacks. These attacks involve manipulating URLs or inputs to access files or directories outside the intended scope, potentially leading to unauthorized access to sensitive files.
http://vulnerable.site/page.php?file=../../../../etc/passwd
The use of -2F (which looks like URL encoding %2F but with hyphens, or perhaps a specific application-level encoding) indicates an attempt to bypass security filters. Many Web Application Firewalls (WAFs) look for the literal string ../.
$base = '/var/www/html/';
$user_path = $base . $_GET['file'];
$real = realpath($user_path);
if ($real === false || strpos($real, $base) !== 0)
die('Invalid path');