Source: cve@mitre.org
Cross-site scripting (XSS) vulnerability in admin/plugin.php in Piwigo through 2.8.3 allows remote attackers to inject arbitrary web script or HTML via a crafted filename that is mishandled in a certain error case.
Piwigo versions through 2.8.3 are vulnerable to a critical cross-site scripting (XSS) attack. This flaw allows attackers to inject malicious JavaScript into the web application via a crafted filename, potentially leading to account compromise, data theft, and complete site takeover. Successful exploitation requires no authentication and can be easily automated.
Step 1: Payload Delivery: The attacker crafts a malicious filename containing JavaScript code (e.g., <script>alert('XSS')</script>).
Step 2: File Upload Attempt: The attacker attempts to upload a file with the crafted filename to the Piwigo instance, likely through the plugin upload functionality.
Step 3: Error Condition Trigger: The upload fails, or an error is generated, potentially due to an invalid file type or other upload restrictions.
Step 4: Error Message Generation: The admin/plugin.php script generates an error message that includes the attacker-controlled filename.
Step 5: XSS Execution: Because the filename is not properly escaped, the injected JavaScript code is rendered in the browser, leading to XSS execution when the administrator views the error message.
The vulnerability stems from improper sanitization of filenames within the admin/plugin.php script of Piwigo. Specifically, when handling file uploads and encountering an error condition (e.g., an invalid file type or upload failure), the application fails to properly escape the filename before displaying it in an error message. This allows an attacker to inject malicious JavaScript code into the filename, which is then rendered in the browser, leading to XSS. The root cause is a lack of input validation and output encoding (specifically, HTML escaping) of user-supplied data (the filename) when displaying error messages. The flaw is not a buffer overflow or race condition but a simple failure to sanitize user input before rendering it in the HTML response. The specific function responsible is likely related to error handling during plugin upload or management.
While no specific APTs are directly linked to this CVE, the ease of exploitation makes it attractive to a wide range of attackers, including those seeking to establish a foothold for further attacks. This vulnerability could be used as an initial access vector. Not listed in CISA KEV.
Web server logs: Examine web server logs for suspicious requests to admin/plugin.php with unusual filenames, especially those containing HTML or JavaScript tags.
Network traffic analysis: Monitor network traffic for POST requests to admin/plugin.php with file uploads. Inspect the content of the uploaded files and the filenames for malicious payloads.
Intrusion Detection Systems (IDS): Implement IDS rules to detect XSS attempts, particularly those targeting the admin/plugin.php script. Look for patterns like <script>, onerror, and other XSS payloads in filenames.
File Integrity Monitoring (FIM): Monitor the integrity of critical Piwigo files, including admin/plugin.php, to detect any unauthorized modifications.
Security Information and Event Management (SIEM): Correlate events from web server logs, IDS, and other security tools to identify potential XSS attacks and suspicious activity.
Upgrade to Piwigo version 2.8.4 or later. This version includes a fix for the XSS vulnerability.
Implement input validation: Ensure that all user-supplied data, including filenames, is properly validated to prevent the injection of malicious code.
Implement output encoding: Properly encode all output, especially when displaying user-supplied data in HTML. This includes HTML escaping to prevent XSS.
Use a Web Application Firewall (WAF): Deploy a WAF to filter malicious requests and prevent XSS attacks.
Regularly scan the Piwigo installation for vulnerabilities using vulnerability scanners.
Apply the principle of least privilege: Restrict the permissions of the Piwigo web server user to minimize the impact of a successful attack.
Keep the web server software (e.g., Apache, Nginx) up to date with the latest security patches.
Implement a strong content security policy (CSP) to mitigate the impact of XSS attacks.