Source: PSIRT-CNA@flexerasoftware.com
Cross-site scripting (XSS) vulnerability in The Address Book 1.04e allows remote attackers to inject arbitrary web script or HTML by uploading the HTML file with a GIF or JPG extension, which is rendered by Internet Explorer.
The Address Book 1.04e is vulnerable to a cross-site scripting (XSS) attack. Attackers can upload malicious HTML files disguised as images, which, when viewed in Internet Explorer, execute arbitrary JavaScript, potentially leading to account compromise and data theft.
Step 1: Payload Creation: The attacker crafts a malicious HTML file containing JavaScript code. This code could be designed to steal cookies, redirect the user to a phishing site, or perform other malicious actions.
Step 2: File Disguise: The attacker saves the malicious HTML file with a .gif or .jpg extension (e.g., malicious.gif).
Step 3: File Upload: The attacker uploads the disguised HTML file to The Address Book 1.04e.
Step 4: Victim Access: A legitimate user of The Address Book 1.04e, using Internet Explorer, views the uploaded file (e.g., by clicking a link or accessing a page that displays the uploaded image).
Step 5: XSS Execution: Internet Explorer, due to its handling of file types and lack of proper content-type validation by the application, renders the HTML content, executing the attacker's JavaScript code.
The vulnerability stems from insufficient input validation and improper content type handling. The Address Book 1.04e allows users to upload files without properly verifying their content. Specifically, it trusts the file extension (.gif, .jpg) to determine the content type. An attacker can craft an HTML file containing malicious JavaScript and save it with a .gif or .jpg extension. When the uploaded file is later accessed by a user with Internet Explorer, the browser renders the HTML content, executing the embedded JavaScript. The root cause is a failure to perform proper content type checking, relying solely on the file extension, and a lack of sanitization of user-supplied data before rendering it in the browser.
This vulnerability is not directly associated with specific APT groups. However, the techniques used (XSS) are commonly employed by various threat actors. The impact of the vulnerability could be used in conjunction with other vulnerabilities to achieve a larger goal. CISA KEV: Not Listed
Network traffic analysis: Look for unusual HTTP requests with image file extensions (.gif, .jpg) containing JavaScript code or suspicious HTML tags.
Web server logs: Examine web server logs for requests to uploaded files with image extensions. Look for unusual user agents (e.g., Internet Explorer).
File system monitoring: Monitor the file system for the creation of files with image extensions that contain HTML or JavaScript code.
Intrusion Detection System (IDS): Implement IDS rules to detect XSS payloads in HTTP requests and responses.
Endpoint Detection and Response (EDR): Monitor endpoint activity for suspicious browser behavior, such as the execution of JavaScript from unexpected sources or the modification of browser settings.
Input Validation: Implement robust input validation to ensure that uploaded files are of the expected type and do not contain malicious code. This includes validating the content type (e.g., using Content-Type headers) and sanitizing user-supplied data.
Content Type Verification: Verify the content type of uploaded files using server-side checks (e.g., using libraries like libmagic or file) rather than relying solely on the file extension.
Output Encoding: Properly encode output to prevent XSS vulnerabilities. This involves escaping special characters in user-supplied data before displaying it in HTML.
Upgrade or Patch: If possible, upgrade The Address Book to a patched version or a more secure alternative. Since the software is old, this might not be possible, so the other remediation steps are more important.
Web Application Firewall (WAF): Deploy a WAF to filter malicious requests and prevent XSS attacks.
Browser Security Configuration: Configure web browsers to mitigate XSS vulnerabilities (e.g., enable Content Security Policy (CSP)).
Educate Users: Train users to be cautious about clicking links or opening files from untrusted sources.