CVE-2025-5377: Astun iShare Maps XSS Vulnerability

CVE-2025-5377 Overview

A Cross-Site Scripting (XSS) vulnerability has been identified in Astun Technology iShare Maps version 5.4.0. The vulnerability exists in the historic1.asp file, where improper handling of the Zoom parameter allows attackers to inject malicious scripts. This reflected XSS vulnerability can be exploited remotely without authentication, potentially enabling session hijacking, credential theft, or malicious content injection targeting users of affected mapping applications.

Critical Impact

Attackers can execute arbitrary JavaScript in the context of authenticated user sessions, potentially leading to session hijacking, credential theft, phishing attacks, or defacement of mapping interfaces.

Affected Products

• Astun Technology iShare Maps 5.4.0
• Web applications utilizing the vulnerable historic1.asp component
• Deployments with exposed mapping interfaces accessible over the network

Discovery Timeline

• May 31, 2025 - CVE-2025-5377 published to NVD
• June 2, 2025 - Last updated in NVD database

Technical Details for CVE-2025-5377

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The flaw resides in the historic1.asp file within Astun Technology iShare Maps 5.4.0. The Zoom parameter accepts user-supplied input that is reflected back in the HTTP response without proper sanitization or encoding.

When a user clicks a maliciously crafted link containing JavaScript in the Zoom parameter, the script executes in the victim's browser within the security context of the iShare Maps application. This can allow attackers to steal session cookies, capture keystrokes, redirect users to phishing pages, or perform actions on behalf of authenticated users. The vulnerability requires user interaction (clicking a malicious link) but can be exploited remotely by any attacker without prior authentication.

Root Cause

The root cause is insufficient input validation and output encoding in the historic1.asp file. The application fails to properly sanitize the Zoom parameter before including it in the rendered HTML response. This allows special characters such as <, >, and quotes to be interpreted as HTML/JavaScript rather than being treated as literal text. The absence of Content Security Policy (CSP) headers may further exacerbate the exploitability of this vulnerability.

Attack Vector

The attack vector is network-based, requiring an attacker to craft a malicious URL containing JavaScript payload in the Zoom parameter. The attacker then distributes this URL through phishing emails, social engineering, or by embedding it on compromised websites. When a victim accesses the malicious URL while authenticated to the iShare Maps application, the injected script executes with the victim's session privileges.

The vulnerability can be exploited through reflected XSS payloads injected via the Zoom parameter in requests to historic1.asp. Attackers craft URLs containing malicious JavaScript that, when clicked by victims, execute in the context of the user's authenticated session. This enables theft of session tokens, credential harvesting through fake login forms, or redirection to attacker-controlled domains. Technical details are available in the VulDB entry #310670.

Detection Methods for CVE-2025-5377

Indicators of Compromise

• Unusual URL patterns in web server logs containing script tags or JavaScript event handlers in the Zoom parameter of historic1.asp requests
• Requests to historic1.asp with URL-encoded or obfuscated payloads such as %3Cscript%3E or javascript: patterns
• Client-side alerts from endpoint protection detecting script injection attempts or suspicious redirect behavior
• User reports of unexpected behavior, pop-ups, or credential prompts when accessing iShare Maps

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block XSS patterns in URL parameters targeting historic1.asp
• Implement log analysis to identify requests with suspicious characters or encoding in the Zoom parameter
• Configure browser-based XSS auditors and Content Security Policy violation reporting
• Monitor for anomalous outbound connections from client browsers after accessing mapping interfaces

Monitoring Recommendations

• Enable detailed access logging for ASP files and review logs for injection patterns in query strings
• Set up real-time alerting for requests containing common XSS payloads such as <script>, onerror=, or javascript:
• Monitor client-side telemetry for unexpected script execution or DOM manipulation on iShare Maps pages
• Review authentication logs for session anomalies that may indicate token theft following XSS exploitation

How to Mitigate CVE-2025-5377

Immediate Actions Required

• Apply input validation to the Zoom parameter in historic1.asp to allow only expected numeric or alphanumeric values
• Implement output encoding (HTML entity encoding) for all user-supplied input reflected in responses
• Deploy Content Security Policy (CSP) headers to restrict inline script execution and limit script sources
• Consider temporarily restricting access to historic1.asp or the affected mapping functionality until a vendor patch is available

Patch Information

The vendor (Astun Technology) was contacted about this vulnerability but did not respond at the time of disclosure. No official patch is currently available. Organizations should monitor the vendor's security advisories and the VulDB entry for updates regarding an official fix.

Workarounds

• Implement server-side input validation to reject requests containing HTML tags or script patterns in the Zoom parameter
• Deploy a Web Application Firewall (WAF) with XSS detection rules to filter malicious requests before they reach the application
• Apply output encoding at the application layer using server-side functions to encode special characters before rendering
• Implement strict Content Security Policy headers to prevent execution of inline scripts, significantly reducing XSS impact

Organizations should implement URL parameter validation at the server level to ensure the Zoom parameter only accepts expected numeric values. A basic validation approach would reject any requests containing HTML special characters or script patterns. Additionally, implementing HTTP response headers such as Content-Security-Policy and X-XSS-Protection provides defense-in-depth against exploitation attempts.