CVE-2017-14981 in ATutor
Summary
by MITRE
Cross-Site Scripting (XSS) was discovered in ATutor before 2.2.3. The vulnerability exists due to insufficient filtration of data (url in /mods/_standard/rss_feeds/edit_feed.php). An attacker could inject arbitrary HTML and script code into a browser in the context of the vulnerable website.
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Analysis
by VulDB Data Team • 12/30/2022
The vulnerability identified as CVE-2017-14981 represents a critical cross-site scripting flaw in ATutor version 2.2.2 and earlier, classified under CWE-79 as improper neutralization of input during web output. This vulnerability specifically affects the rss_feeds module within the ATutor learning management system, where the application fails to properly sanitize user-supplied URL parameters before rendering them in web pages. The flaw occurs in the edit_feed.php file where unfiltered input allows malicious actors to inject HTML and JavaScript code that executes within the context of legitimate user sessions. The vulnerability stems from the application's inadequate validation and sanitization mechanisms that should have been implemented to prevent malicious data from being processed and displayed without proper encoding or filtering.
The operational impact of this XSS vulnerability is significant as it enables attackers to execute arbitrary scripts in the browsers of unsuspecting users who visit affected pages. An attacker could exploit this weakness by crafting malicious URLs containing script payloads that would be stored and subsequently executed when other users view the RSS feed configuration page. This type of vulnerability creates a persistent threat vector where malicious code could steal session cookies, redirect users to phishing sites, or perform unauthorized actions on behalf of authenticated users. The vulnerability is particularly dangerous in educational environments where ATutor is deployed, as it could compromise the security of student and instructor accounts, potentially leading to data breaches and unauthorized access to sensitive learning materials.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1566 for phishing, as it enables attackers to deliver malicious payloads through web-based attack vectors. The exploitation requires minimal technical skill and can be automated through social engineering tactics where users are tricked into clicking malicious links. The vulnerability demonstrates a failure in the principle of least privilege and input validation, as the application should have implemented proper output encoding and input sanitization mechanisms. The attack surface is relatively narrow since it requires access to the specific rss_feeds module and knowledge of the vulnerable file path, but the impact remains severe due to the potential for session hijacking and privilege escalation.
The recommended mitigation strategy involves applying the official patch released by ATutor for version 2.2.3, which implements proper input validation and output encoding for URL parameters in the affected module. Organizations should also implement additional security measures including web application firewalls, content security policies, and regular security audits of web applications. The fix should include implementing proper HTML entity encoding for all user-supplied data before rendering in web contexts, as well as input validation that rejects suspicious characters and patterns commonly associated with XSS attacks. Security teams should conduct thorough vulnerability assessments to identify similar issues in other modules and ensure that all user inputs are properly sanitized regardless of their source or intended use within the application.