Path Traversal

(Redirigido desde «Path traversal»)
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This is an Attack. To view all attacks, please see the Attack Category page.

Last revision (mm/dd/yy): 10/6/2015


A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (../)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. It should be noted that access to files is limited by system operational access control (such as in the case of locked or in-use files on the Microsoft Windows operating system).

This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.

Related Security Activities

How to Avoid Path Traversal Vulnerabilities

See the OWASP Guide article on how to Avoid Path Traversal Vulnerabilities.

How to Test for Path Traversal Vulnerabilities

See the OWASP Testing Guide article on how to Test for Path Traversal Vulnerabilities.


Request variations

Encoding and double encoding:

%2e%2e%2f represents ../
%2e%2e/ represents ../
..%2f represents ../ 
%2e%2e%5c represents ..\
%2e%2e\ represents ..\ 
..%5c represents ..\ 
%252e%252e%255c represents ..\ 
..%255c represents ..\ and so on. 

Percent encoding (aka URL encoding)

Note that web containers perform one level of decoding on percent encoded values from forms and URLs.

..%c0%af represents ../ 
..%c1%9c represents ..\ 

OS specific


Root directory:  “ / “ 
Directory separator: “ / “


Root directory: “  <partition letter> : \ “
Directory separator: “ / “ or “ \ ” 
Note that windows allows filenames to be followed by extra . \ / characters.

In many operating systems, null bytes %00 can be injected to terminate the filename. For example, sending a parameter like:


will result in the Java application seeing a string that ends with ".pdf" and the operating system will see a file that ends in ".doc". Attackers may use this trick to bypass validation routines.


Example 1

The following examples show how the application deals with the resources in use.  

In these examples it’s possible to insert a malicious string as the variable parameter to access files located outside the web publish directory. dir/some file dir/some file 

The following URLs show examples of *NIX password file exploitation. 

Note: In a windows system an attacker can navigate only in a partition that locates web root while in the Linux he can navigate in the whole disk.

Example 2

It's also possible to include files and scripts located on external website.   

Example 3

These examples illustrate a case when an attacker made the server show the CGI source code.   

Example 4

This example was extracted from: Wikipedia - Directory Traversal

A typical example of vulnerable application code is:

$template = 'blue.php';
if ( is_set( $_COOKIE['TEMPLATE'] ) )
   $template = $_COOKIE['TEMPLATE'];
include ( "/home/users/phpguru/templates/" . $template );

An attack against this system could be to send the following HTTP request:

GET /vulnerable.php HTTP/1.0
Cookie: TEMPLATE=../../../../../../../../../etc/passwd

Generating a server response such as:

HTTP/1.0 200 OK
Content-Type: text/html
Server: Apache

root:fi3sED95ibqR6:0:1:System Operator:/:/bin/ksh 

The repeated ../ characters after /home/users/phpguru/templates/ has caused include() to traverse to the root directory, and then include the UNIX password file /etc/passwd.

UNIX etc/passwd is a common file used to demonstrate directory traversal, as it is often used by crackers to try cracking the passwords.

Absolute Path Traversal

The following URLs may be vulnerable to this attack:

An attacker can execute this attack like this:

When the web server returns information about errors in a web application, it is much easier for the attacker to guess the correct locations (e.g. path to the file with a source code, which then may be displayed).

Related Threat Agents

Related Attacks

Related Vulnerabilities

Related Controls