CVE-2017-20248: Apptha Slider Gallery Path Traversal

CVE-2017-20248 Overview

CVE-2017-20248 is a path traversal vulnerability [CWE-22] in Apptha Slider Gallery 1.0, a WordPress plugin. The flaw resides in the asgallDownload.php script, which fails to validate the imgname parameter. Unauthenticated remote attackers can supply directory traversal sequences (../) to read arbitrary files outside the intended directory. Successful exploitation enables disclosure of sensitive files such as WordPress configuration data, credentials, and source code.

Critical Impact
Unauthenticated attackers can download arbitrary files from the web server, including wp-config.php and other sensitive resources containing database credentials and secret keys.

Affected Products

Apptha Slider Gallery WordPress plugin version 1.0
WordPress installations bundling the vulnerable asgallDownload.php handler
Any deployment exposing the plugin's download endpoint to untrusted networks

Discovery Timeline

2026-06-09 - CVE-2017-20248 published to NVD
2026-06-09 - Last updated in NVD database

Technical Details for CVE-2017-20248

Vulnerability Analysis

The vulnerability stems from missing input validation in the asgallDownload.php endpoint of Apptha Slider Gallery 1.0. The script accepts a user-supplied imgname parameter and uses it directly to construct a file path for download. Because the parameter is not sanitized or constrained to the plugin's image directory, attackers can inject ../ sequences to traverse the filesystem.

The handler then reads the resolved file and returns its contents in the HTTP response. This grants unauthenticated read access to any file the web server process can access. Targets include wp-config.php, /etc/passwd, application source code, and backup files. Attackers commonly chain this primitive with credential reuse or follow-on database access to escalate impact.

Root Cause

The root cause is improper limitation of a pathname to a restricted directory, classified as [CWE-22]. The plugin neither normalizes the user-supplied path nor verifies that the canonicalized target resides within an allowlisted base directory. No authentication or capability check is enforced before file retrieval.

Attack Vector

The attack vector is network-based and requires no authentication, privileges, or user interaction. An attacker issues an HTTP GET request to the plugin's asgallDownload.php endpoint with a crafted imgname value containing repeated ../ sequences followed by the target file path. The server responds with the file contents. A public proof of concept is documented in Exploit-DB #41568 and the VulnCheck WordPress Advisory.

Detection Methods for CVE-2017-20248

Indicators of Compromise

HTTP requests to asgallDownload.php containing ../ or URL-encoded %2e%2e%2f sequences in the imgname parameter
Web server access logs showing successful 200 responses for imgname values referencing files outside the plugin directory
Outbound transfers of wp-config.php, .htaccess, or other sensitive files originating from the web server
Unusual file read activity by the web server process targeting paths above the WordPress document root

Detection Strategies

Deploy web application firewall (WAF) rules that block path traversal patterns in query strings to asgallDownload.php
Inspect access logs for requests matching the regex asgallDownload\.php.*imgname=.*\.\./
Correlate file reads of wp-config.php with concurrent HTTP requests to the plugin endpoint
Alert on download responses where the served filename differs from expected image extensions (.jpg, .png, .gif)

Monitoring Recommendations

Forward WordPress and web server logs to a centralized SIEM for path traversal pattern analysis
Enable file integrity monitoring on wp-config.php and other sensitive configuration files
Track repeated 200-response requests to plugin download endpoints from a single source IP

How to Mitigate CVE-2017-20248

Immediate Actions Required

Remove or disable the Apptha Slider Gallery 1.0 plugin until a fixed version is available
Restrict access to asgallDownload.php at the web server or WAF layer
Rotate any credentials, API keys, or secrets stored in wp-config.php if exposure is suspected
Audit web server logs for prior exploitation attempts against the plugin endpoint

Patch Information

No vendor patch is referenced in the CVE record. Refer to the Apptha Official Website for vendor updates and the VulnCheck WordPress Advisory for advisory tracking. Replace the plugin with a maintained alternative if no fix is published.

Workarounds

Block requests to asgallDownload.php using web server rewrite rules or .htaccess deny directives
Configure a WAF rule to reject any request containing ../ or encoded variants in the imgname parameter
Run the web server under a least-privilege account that cannot read wp-config.php or system files outside the document root
Apply SELinux or AppArmor profiles to constrain the PHP worker process to the WordPress directory

bash

# Configuration example - Apache block for vulnerable endpoint
<Files "asgallDownload.php">
    Require all denied
</Files>

# Nginx equivalent
location ~* /asgallDownload\.php$ {
    deny all;
    return 403;
}