Source: audit@patchstack.com
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Ays Pro Survey Maker survey-maker allows Stored XSS.This issue affects Survey Maker: from n/a through <= 5.1.8.8.
Stored Cross-Site Scripting (XSS) vulnerabilities in the Ays Pro Survey Maker plugin allow attackers to inject malicious JavaScript code into survey content. This can lead to account compromise, data theft, and website defacement, impacting users who interact with the compromised surveys. Successful exploitation requires no special privileges and can be easily automated.
Step 1: Payload Injection: An attacker crafts a malicious JavaScript payload (e.g., <script>alert('XSS');</script>) designed to execute within a user's browser.
Step 2: Survey Creation/Modification: The attacker, using an account with sufficient privileges (or exploiting a different vulnerability to gain access), injects the payload into a vulnerable field within the Survey Maker plugin, such as a survey question, answer option, or survey description.
Step 3: Data Storage: The plugin stores the malicious payload within its database, along with the other survey data.
Step 4: Survey Delivery: A legitimate user accesses the compromised survey through a web browser.
Step 5: Payload Rendering: The Survey Maker plugin retrieves the survey data, including the attacker's payload, from the database.
Step 6: Unsanitized Output: The plugin renders the survey data directly into the HTML output without proper sanitization or encoding.
Step 7: Payload Execution: The user's browser parses the HTML, encounters the injected JavaScript payload, and executes it. This allows the attacker's code to run within the context of the user's browser, enabling malicious actions.
The vulnerability stems from improper input validation and output encoding within the Ays Pro Survey Maker plugin. Specifically, the plugin fails to adequately sanitize user-supplied input when generating survey pages. This allows attackers to inject malicious JavaScript code into survey question text, answer options, or other fields. When a user views the compromised survey, the injected script executes within their browser, enabling a range of attacks, including cookie theft, session hijacking, and redirection to malicious websites. The root cause is a lack of proper HTML encoding or escaping of user-provided data before it is rendered in the survey's HTML output. This allows the attacker to bypass any client-side input validation and inject arbitrary JavaScript code. The absence of a Content Security Policy (CSP) further exacerbates the issue, as it would otherwise mitigate the impact of the injected scripts.
While no specific APT groups are definitively linked to this vulnerability at this time, the ease of exploitation and potential impact make it attractive to various threat actors. The vulnerability could be leveraged by financially motivated attackers for credential harvesting or malware distribution. It is unlikely to be in CISA KEV due to the nature of the vulnerability, but it could be added if actively exploited at a large scale.
Monitor web server logs for suspicious HTTP requests containing JavaScript payloads (e.g., <script>, onerror, onload).
Implement a Web Application Firewall (WAF) to detect and block XSS attempts based on signature-based and behavior-based rules.
Analyze survey content and database entries for unexpected HTML tags or JavaScript code.
Monitor browser console logs for JavaScript errors or unexpected script execution when accessing surveys.
Network traffic analysis for unusual HTTP requests originating from the survey pages, especially those containing JavaScript payloads.
Upgrade the Ays Pro Survey Maker plugin to version 5.1.8.9 or later.
Implement proper input validation to sanitize all user-supplied data before storing it in the database.
Implement output encoding (e.g., HTML escaping) to ensure that user-supplied data is rendered safely in the HTML output.
Implement a Content Security Policy (CSP) to restrict the execution of JavaScript code to trusted sources, mitigating the impact of XSS attacks.
Regularly scan the website for vulnerabilities using automated tools.
Review and harden the web server configuration to prevent unauthorized access and mitigate potential attack vectors.