CVE-2017-20257: Joomla! Component Quiz Deluxe SQL Injection

CVE-2017-20257 describes an unauthenticated SQL injection vulnerability affecting the Joomla! Component Quiz Deluxe version 3.7.4. This critical flaw allows remote attackers to execute arbitrary SQL commands against the backend database. Attackers achieve this by injecting malicious SQL code into specific parameters (stu_quiz_id or flag_quest) when making requests to the ajaxaction.flag_question task within the component. The vulnerability's re-publication or update in the NVD on 2026-06-19 highlights its continued relevance. Successful exploitation could lead to full database compromise, including sensitive data exfiltration, data manipulation, and potentially further compromise of the web application.

Attack Chain

1. An unauthenticated attacker identifies a public-facing Joomla! instance running the vulnerable Quiz Deluxe component version 3.7.4.
2. The attacker crafts a specially designed HTTP GET or POST request targeting the /index.php endpoint with the option=com_quizdeluxe&task=ajaxaction.flag_question parameters.
3. Malicious SQL payloads, such as ' OR 1=1-- or UNION SELECT ..., are injected into either the stu_quiz_id or flag_quest parameters within the HTTP request.
4. The vulnerable Quiz Deluxe component processes the request without proper input sanitization, leading to the execution of the embedded SQL commands on the backend database.
5. The attacker observes the web server's response for error messages, altered content, or retrieved data, confirming successful injection.
6. Through iterative exploitation, the attacker manipulates database queries to extract sensitive information, such as user credentials, personal identifiable information (PII), or internal application data.
7. The attacker may also use the SQL injection to modify database records, potentially leading to website defacement, privilege escalation, or further compromise of the web application.

Impact

Successful exploitation of CVE-2017-20257 grants unauthenticated attackers the ability to execute arbitrary SQL commands, severely compromising the integrity and confidentiality of the application's database. This directly leads to the exfiltration of sensitive information, including user credentials, proprietary business data, or personally identifiable information (PII) of customers. Attackers can also manipulate existing data, causing data integrity issues or unauthorized content changes on the Joomla! site. Organizations utilizing the affected component version face significant risks of severe data breaches, reputational damage, and potential regulatory compliance violations.

Recommendation

• Immediately patch or upgrade the Joomla! Component Quiz Deluxe to a version greater than 3.7.4 to remediate CVE-2017-20257.
• Deploy the Sigma rules in this brief to your web application firewall (WAF) or SIEM to detect exploitation attempts targeting ajaxaction.flag_question.
• Ensure web server logging (e.g., Apache access logs, Nginx access logs, IIS logs) captures full HTTP request details including URL paths and query parameters to enable detection of SQL injection attempts.
• Implement robust input validation and parameterized queries in all web applications to prevent similar SQL injection vulnerabilities.