CVE-2017-20267: SQL Injection in Joomla! Calendar Planner 1.0.1

Technical summary

CVE-2017-20267 is a classic SQL injection vulnerability (CWE-89) in the Calendar Planner Joomla! component affecting version 1.0.1. The vulnerability exists in the events view's handling of the category_id parameter, which fails to properly sanitize or parameterize user input before incorporating it into SQL queries. An unauthenticated attacker can submit crafted SQL syntax through the GET parameter to manipulate the query logic, enabling extraction of arbitrary database records. The CVSS 3.1 score of 8.2 reflects the high confidentiality impact, modest integrity impact (potential for data modification depending on database permissions), and absence of availability impact.

Business impact

Successful exploitation could result in unauthorized access to sensitive business data stored in the Joomla! database, including user credentials, personal information, configuration details, and proprietary content. While the vulnerability does not directly enable deletion or system-wide disruption, attackers can read and potentially modify data, leading to compliance violations (GDPR, HIPAA, PCI-DSS), reputational harm, and breach notification obligations. Organizations relying on the Calendar Planner component for customer-facing scheduling or internal event management face elevated risk if the component is exposed to untrusted networks.

Affected systems

Joomla! installations using Calendar Planner component version 1.0.1 are affected. No evidence of the vulnerability in other versions has been documented in this advisory; however, organizations should verify whether their deployed version is within scope and whether any earlier or later versions may contain similar flaws by consulting the component vendor's security bulletins.

Exploitability

This vulnerability exhibits high exploitability. The attack vector is network-based, requires no authentication, no user interaction, and no special privileges. A simple HTTP GET request with injected SQL syntax is sufficient to trigger the flaw. No specialized tools beyond a web browser or curl are required. However, exploitation success depends on the attacker's knowledge of the database schema and the specific SQL dialect in use; blind SQL injection techniques may be necessary if error messages are suppressed. The vulnerability is not currently tracked in the CISA Known Exploited Vulnerabilities catalog.

Remediation

Immediate action is required: disable or remove the Calendar Planner component version 1.0.1 if it is not essential to operations. Contact the component vendor to determine whether a patched version is available; if a fix exists, prioritize upgrading to the latest patched release. As an interim measure, implement Web Application Firewall (WAF) rules to detect and block SQL injection patterns in the category_id parameter, and restrict network access to the Joomla! administration interface and affected views to trusted IP ranges. Conduct a security audit of your Joomla! installation to identify whether similar input validation weaknesses exist in other components.

Patch guidance

Verify the availability of a patched version from the Calendar Planner component vendor. Update guidance should reference the vendor's official security advisory and release notes. Apply patches in a controlled manner: test in a staging environment first to ensure compatibility with your Joomla! version and any dependent extensions, then deploy to production during a maintenance window. After patching, validate that the category_id parameter is properly escaped and that the WAF rules are adjusted if they were previously in place as a workaround.

Detection guidance

Monitor web server and application logs for GET requests to the events view containing unusual SQL syntax in the category_id parameter (e.g., single quotes, SQL keywords like UNION, SELECT, OR, comments such as -- or /**/). Deploy Web Application Firewall rules targeting CWE-89 patterns. Implement database activity monitoring to detect unexpected queries or data access patterns originating from the web application tier. Consider enabling verbose error logging to catch failed injection attempts, but ensure error messages are not exposed to end users. Check for indicators of compromise such as new database user accounts, altered table structures, or unusual data exports from the application logs.

Why prioritize this

This vulnerability merits high prioritization due to its CVSS 8.2 severity, unauthenticated network exploitability, and direct impact on confidentiality and integrity of sensitive database content. The simplicity of exploitation means remediation delay increases breach risk. Organizations using the affected component should treat this as a critical issue requiring immediate patching or mitigation.

Risk score, explained

The CVSS 3.1 score of 8.2 (HIGH) reflects: (1) network-based attack vector requiring no user interaction or privileges; (2) low complexity, meaning the attack can be mounted with basic tools; (3) high confidentiality impact, as attackers can read arbitrary database records; (4) low integrity impact, suggesting limited ability to modify critical system files or configurations (though database modification is possible); (5) no availability impact, as the vulnerability does not enable denial of service. The score appropriately captures the serious but not catastrophic nature of the flaw.

Frequently asked questions