-view-php-3a-2f-2ffilter-2fread-3dconvert.base64 Encode-2fresource-3d-2froot-2f.aws-2fcredentials Direct

Feature: Secure AWS Credential Handling with Base64 Encoding/Decoding

Real Breaches Attributable to LFI + Exposed Creds

Capital One (2019): An SSRF (similar family to LFI) allowed reading from the AWS metadata service, not exactly this payload, but related.
Numerous bug bounty reports: Attackers frequently find .aws/credentials via path traversal and LFI in high-severity reports.

Vulnerable Code Example

// Evil example – do not use
$page = $_GET['page'];
include($page . ".php");

An attacker can supply: ?page=php://filter/convert.base64-encode/resource=/root/.aws/credentials

The .php concatenation might break some wrappers, but advanced payloads or null byte injection (%00) can bypass this. Alternatively, if the application uses functions like file_get_contents() or readfile() without suffix addition, the wrapper works directly. Capital One (2019) : An SSRF (similar family

Security Considerations

Access Control: Ensure only authorized users can access and execute this functionality, especially since it involves reading sensitive AWS credentials.
Input Validation: Validate and sanitize any input paths to prevent unauthorized access to files.
Error Handling: Implement robust error handling to manage scenarios where files cannot be read or encoded.

The Vulnerability Concept

This specific payload targets a Local File Inclusion (LFI) vulnerability. LFI occurs when an application allows user input to control the path of a file that the server attempts to read or include. Vulnerable Code Example // Evil example – do

In a vulnerable PHP application, the code might look something like this: which helps attackers find other vulnerabilities.

<?php
   // Vulnerable code example
   $file = $_GET['file'];
   include($file);
?>

If an attacker passes the php://filter wrapper as the input, the PHP engine processes the wrapper instead of treating it strictly as a file path. This allows the attacker to read the source code of sensitive files on the server, potentially leading to:

Credential Theft: Exposing database passwords or API keys (as in the AWS credentials example).
Source Code Disclosure: Revealing application logic, which helps attackers find other vulnerabilities.