Source: cna@vuldb.com
A vulnerability was detected in SourceCodester Modern Image Gallery App 1.0. Affected by this vulnerability is an unknown functionality of the file upload.php. The manipulation of the argument filename results in cross site scripting. The attack may be launched remotely. The exploit is now public and may be used.
SourceCodester Modern Image Gallery App 1.0 is vulnerable to a cross-site scripting (XSS) attack due to insufficient input validation in the upload.php file, allowing attackers to inject malicious JavaScript code. This vulnerability enables remote attackers to execute arbitrary code in the context of a victim's browser, potentially leading to account compromise and data theft.
Step 1: Payload Delivery: The attacker crafts a malicious filename containing JavaScript code (e.g., <script>alert('XSS')</script>).
Step 2: File Upload: The attacker uploads a file with the crafted malicious filename to the upload.php script.
Step 3: Server Storage: The upload.php script stores the uploaded file, including the malicious filename, on the server.
Step 4: Victim Interaction: A user views the image gallery or accesses a page that displays the uploaded image or links to it.
Step 5: XSS Execution: The browser renders the image or its associated metadata, including the malicious filename. The injected JavaScript code is executed within the context of the user's browser, triggering the XSS attack.
The vulnerability stems from a lack of proper sanitization of the filename parameter within the upload.php script. The application fails to adequately validate or encode user-supplied input before incorporating it into the HTML response. This allows an attacker to inject malicious JavaScript code within the filename, which is then rendered by the browser when the image is displayed or linked. The root cause is a missing or inadequate input validation and output encoding mechanism, specifically failing to sanitize the filename before it is used in the HTML output. This leads to a stored XSS vulnerability.
While no specific APTs are directly linked in the provided information, the public availability of the exploit and the nature of XSS vulnerabilities make it attractive to a wide range of attackers, including those seeking to steal credentials, deface websites, or distribute malware. This vulnerability does not have a CISA KEV status.
Network traffic analysis: Examine HTTP requests to upload.php for suspicious filenames containing HTML tags or JavaScript code.
Web server logs: Monitor web server logs for requests to upload.php with unusual filenames, especially those containing <script> tags or other potentially malicious code.
File system monitoring: Scan the file system for newly uploaded files with filenames that appear to be malicious (e.g., containing HTML tags).
Intrusion Detection/Prevention Systems (IDS/IPS): Implement rules to detect XSS attempts, specifically those targeting the upload.php script and the filename parameter.
Security Information and Event Management (SIEM): Correlate log data from web servers, file systems, and IDS/IPS to identify potential XSS attacks.
Input Validation: Implement robust input validation on the filename parameter to sanitize and filter out potentially malicious characters (e.g., <, >, &, ', "). Use a whitelist approach, allowing only alphanumeric characters and specific allowed characters.
Output Encoding: Properly encode the filename parameter when it is used in HTML output (e.g., using HTML entity encoding) to prevent the browser from interpreting the injected code.
Content Security Policy (CSP): Implement a Content Security Policy (CSP) to restrict the sources from which the browser can load resources, mitigating the impact of XSS attacks.
Regular Security Audits: Conduct regular security audits and penetration testing to identify and address vulnerabilities.
Keep Software Updated: Ensure the SourceCodester Modern Image Gallery App is updated to the latest version, or, if no patch is available, consider removing the vulnerable component.
Web Application Firewall (WAF): Deploy a WAF to filter malicious requests and protect against XSS attacks.