CVE-2025-49454

Executive Summary

CVE-2025-49454 is a critical PHP Local File Inclusion (LFI) vulnerability affecting the LoftOcean TinySalt WordPress plugin, versions prior to 3.10.0. The vulnerability stems from improper control of filenames used in PHP include/require statements, allowing an unauthenticated attacker to include arbitrary local files from the server. This can lead to sensitive information disclosure, remote code execution (if combined with file upload), and full server compromise. The CVSS score of 8.1 (High) reflects the low attack complexity and network-based vector. No public proof-of-concept or patch details are currently available, but the vendor has been notified.

Supply Chain & Package Security

This vulnerability affects the WordPress plugin ecosystem. Since TinySalt is distributed via the WordPress plugin repository, any site running a version below 3.10.0 is at risk. Administrators should immediately check their plugin version and apply any available updates. The lack of a public patch increases the urgency for manual mitigation.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – Vulnerability does not affect other components.
• Confidentiality (C): High (H) – Full file read capability.
• Integrity (I): High (H) – Potential for code execution.
• Availability (A): High (H) – Could lead to denial of service.

Threat Level: High. The combination of network exploitability, low complexity, and no authentication makes this a prime target for automated scanning and exploitation.

Deep Dive & Mechanics

The vulnerability is a PHP Local File Inclusion (LFI) in the TinySalt plugin. The plugin likely uses a dynamic include or require statement where the filename is partially or fully controlled by user input (e.g., via a GET/POST parameter). An attacker can manipulate this parameter to include arbitrary files from the server, such as /etc/passwd, log files, or PHP wrappers like php://filter for code execution.

Root Cause: The plugin fails to sanitize or validate the filename parameter before passing it to a PHP include function. This is a classic CWE-98: Improper Control of Filename for Include/Require Statement in PHP Program.

Attack Flow:

1. Attacker identifies a vulnerable endpoint (e.g., ?page=... or ?template=...).
2. Attacker sends a request with a path traversal payload (e.g., ../../../../etc/passwd).
3. The server includes the specified file, exposing its contents in the response.
4. If the attacker can also upload a file (e.g., via another plugin or feature), they can include that file to achieve remote code execution.

Vulnerable vs. Patched Code

Vulnerable Code (Hypothetical):

<?php
$page = $_GET['page'];
include("pages/" . $page . ".php");
?>

Patched Code (Hypothetical):

<?php
$page = $_GET['page'];
$allowed_pages = array('home', 'about', 'contact');
if (in_array($page, $allowed_pages)) {
    include("pages/" . $page . ".php");
} else {
    // Handle error
}
?>

The patched version uses a whitelist of allowed filenames, preventing arbitrary file inclusion.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Install a vulnerable version of TinySalt (e.g., 3.9.9) on a WordPress instance.
2. Identify the vulnerable parameter (e.g., ?template=).
3. Use a tool like curl or Burp Suite to test.

Exploitation Steps:

1. Basic LFI to read /etc/passwd:

   curl "http://target/wp-content/plugins/tinysalt/vuln.php?template=../../../../etc/passwd"
   

2. Using PHP wrappers for code execution (if file upload is possible):

   curl "http://target/wp-content/plugins/tinysalt/vuln.php?template=php://filter/convert.base64-encode/resource=../../../../etc/passwd"
   

3. For RCE via log poisoning:
   • Inject PHP code into User-Agent header.
   • Include the access log file.

Blue Team (Defensive)

Detection:

• Monitor for path traversal patterns in GET/POST parameters (e.g., ../, ..\\, %2e%2e%2f).
• Alert on attempts to include sensitive files like /etc/passwd, /etc/shadow, or Windows equivalents.
• Use WAF rules to block php:// and expect:// wrappers.

Mitigation:

• Immediately update TinySalt to version 3.10.0 or later.
• If no patch is available, disable the plugin or implement a virtual patch via WAF.
• Restrict file permissions on the server to limit the impact of LFI.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests containing ../ or ..\\ in parameters.
  • Requests to wp-content/plugins/tinysalt/ with suspicious parameters.
  • User-Agent strings containing PHP code (e.g., <?php system($_GET['cmd']); ?>).
• File IOCs:
  • Unexpected files in /tmp/ or web-accessible directories.
  • Modified .htaccess or wp-config.php files.
• Log IOCs:
  • Access logs showing attempts to include /etc/passwd or /proc/self/environ.

Detection Engineering

YARA Rule

rule CVE_2025_49454_LFI_Detection {
    meta:
        description = "Detects LFI attempts targeting TinySalt plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-49454"
    strings:
        $path_traversal = /\.\.\/|\.\.\\|%2e%2e%2f|%2e%2e%5c/
        $sensitive_file = /etc\/passwd|etc\/shadow|boot\.ini|windows\/win\.ini/
        $php_wrapper = /php:\/\/|expect:\/\//
    condition:
        any of ($path_traversal) and any of ($sensitive_file) or any of ($php_wrapper)
}

Sigma Rule

title: CVE-2025-49454 TinySalt LFI Attempt
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects path traversal attempts in TinySalt plugin
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains:
            - '../'
            - '..\\'
            - '%2e%2e%2f'
            - '%2e%2e%5c'
        c-uri|contains:
            - '/etc/passwd'
            - '/etc/shadow'
            - 'boot.ini'
    condition: selection
falsepositives:
    - Legitimate use of path traversal in other applications
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-49454 TinySalt LFI Attempt"; flow:to_server,established; content:"../"; http_uri; nocase; content:"/etc/passwd"; http_uri; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Disable the TinySalt plugin until a patch is applied.
2. Update: Upgrade to version 3.10.0 or later as soon as it becomes available.
3. Virtual Patching: Use a Web Application Firewall (WAF) to block path traversal patterns and PHP wrappers.
4. File Permissions: Ensure that sensitive files (e.g., /etc/passwd, wp-config.php) are not readable by the web server user.
5. Monitoring: Enable logging and alerting for LFI attempts using the provided detection rules.
6. Code Review: If you are a developer, implement input validation and whitelisting for all file inclusion operations.

Valters IT signature: This report is generated for educational and defensive purposes. Unauthorized exploitation of this vulnerability is illegal.