CVE-2017-20257: Quiz Deluxe SQLi Vulnerability

CVE-2017-20257 Overview

CVE-2017-20257 is an SQL injection vulnerability in the Joomla! Quiz Deluxe component version 3.7.4 from JoomPlace. The flaw resides in the ajaxaction.flag_question task, where the stu_quiz_id and flag_quest parameters are passed directly into database queries without sanitization. Unauthenticated remote attackers can inject arbitrary SQL statements to read sensitive data from the Joomla database, including user credentials and session tokens. The vulnerability is classified under CWE-89: Improper Neutralization of Special Elements used in an SQL Command.

Critical Impact
Remote unauthenticated attackers can extract arbitrary data from the backend database of any Joomla site running Quiz Deluxe 3.7.4.

Affected Products

JoomPlace Quiz Deluxe Joomla! extension, version 3.7.4
Joomla! installations with the Quiz Deluxe component enabled
Web applications exposing the ajaxaction.flag_question endpoint

Discovery Timeline

2026-06-19 - CVE-2017-20257 published to NVD
2026-06-22 - Last updated in NVD database

Technical Details for CVE-2017-20257

Vulnerability Analysis

The vulnerability exists in the AJAX handler routed through the ajaxaction.flag_question task within the Quiz Deluxe extension. Attacker-controlled values for stu_quiz_id and flag_quest are concatenated into SQL statements without parameterization or input validation. An attacker can send a crafted HTTP request to the Joomla front controller and trigger arbitrary SQL execution against the underlying MySQL database. Successful exploitation enables data extraction through UNION-based or boolean-based blind injection techniques. Because the endpoint does not require authentication, exploitation can be automated at scale across exposed Joomla sites.

Root Cause

The root cause is the absence of prepared statements and input sanitization on parameters processed by the flag_question action. The component trusts client-supplied identifiers and interpolates them directly into query strings used by the Joomla database abstraction layer. This pattern violates secure coding practice for parameterized queries and falls under [CWE-89].

Attack Vector

Exploitation requires only network access to the Joomla site hosting the vulnerable component. The attacker issues a GET or POST request to the index.php entry point with the task=ajaxaction.flag_question parameter and a malicious payload in stu_quiz_id or flag_quest. No user interaction, session cookie, or privileges are needed. Public exploitation details are documented in Exploit-DB entry 42589 and the VulnCheck advisory.

Detection Methods for CVE-2017-20257

Indicators of Compromise

HTTP requests to index.php containing task=ajaxaction.flag_question combined with SQL metacharacters such as UNION, SELECT, --, or 0x in stu_quiz_id or flag_quest parameters.
Web server access logs showing repeated requests to the Quiz Deluxe AJAX endpoint from a single source within a short timeframe.
Unexpected database errors or long response times correlated with requests targeting the flag_question task.

Detection Strategies

Deploy a Web Application Firewall (WAF) rule that inspects requests to option=com_jquizdeluxe and blocks SQL keywords in user-controlled parameters.
Enable MySQL general query logging and alert on queries originating from the flag_question workflow that contain tautologies like OR 1=1 or UNION SELECT.
Review Joomla error logs for malformed query exceptions tied to the Quiz Deluxe extension.

Monitoring Recommendations

Aggregate web server, WAF, and database logs into a centralized analytics platform and correlate by source IP and URI pattern.
Monitor outbound traffic from the web server for data exfiltration spikes following suspicious requests.
Track failed authentication attempts on the Joomla administrator portal after suspected injection activity, since stolen credentials are a likely follow-on action.

How to Mitigate CVE-2017-20257

Immediate Actions Required

Disable or unpublish the Quiz Deluxe component from the Joomla Extensions Manager until a fixed version is installed.
Restrict access to the Joomla site via IP allowlisting or authentication at the reverse proxy if the extension cannot be removed immediately.
Audit the Joomla user table and session storage for signs of credential theft and force password resets where compromise is suspected.

Patch Information

No vendor patch is referenced in the available advisories from JoomPlace or the Joomla Extensions Directory listing for Quiz Deluxe. Administrators should consult JoomPlace directly for an updated release and apply any version newer than 3.7.4 that addresses the injection.

Workarounds

Remove the Quiz Deluxe extension entirely if a patched version is not available.
Implement WAF signatures that block SQL injection patterns targeting the task=ajaxaction.flag_question endpoint and its parameters.
Apply least-privilege principles to the MySQL account used by Joomla so that successful injection cannot read tables outside the application schema.

bash

# Example ModSecurity rule to block injection attempts against the vulnerable task
SecRule ARGS:task "@streq ajaxaction.flag_question" \
  "id:1020257,phase:2,deny,status:403,\
  chain,msg:'Block CVE-2017-20257 Quiz Deluxe SQLi'"
  SecRule ARGS:stu_quiz_id|ARGS:flag_quest \
    "@rx (?i)(union|select|sleep\(|benchmark\(|--|/\*)"