CVE-2024-0855 in Spiffy Calendar Plugin
Summary
by MITRE • 02/27/2024
The Spiffy Calendar WordPress plugin before 4.9.9 doesn't check the event_author parameter, and allows any user to alter it when creating an event, leading to deceiving users/admins that a page was created by a Contributor+.
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Analysis
by VulDB Data Team • 08/09/2024
The vulnerability identified as CVE-2024-0855 affects the Spiffy Calendar WordPress plugin version 4.9.8 and earlier, representing a critical authorization flaw that undermines the integrity of user permissions within WordPress environments. This issue stems from insufficient input validation and access control mechanisms within the plugin's event creation functionality, creating a scenario where unauthorized users can manipulate the event_author parameter during event submission processes. The flaw directly violates fundamental security principles by allowing privilege escalation through parameter manipulation, enabling attackers to spoof authorship of calendar events and potentially mislead administrators and end users about the true origin of content.
The technical implementation of this vulnerability occurs within the plugin's event creation endpoint where the event_author parameter is not properly validated or sanitized before being stored in the database. This parameter typically should be restricted to the currently authenticated user or administrators with appropriate privileges, but the plugin fails to enforce these restrictions. Attackers can exploit this by crafting malicious requests that include arbitrary user IDs in the event_author field, effectively allowing them to associate calendar events with accounts possessing higher privileges than their own. The vulnerability is classified under CWE-285: Improper Authorization, which specifically addresses situations where systems fail to properly verify that an actor is authorized to perform a requested operation.
From an operational perspective, this vulnerability creates significant risks for WordPress administrators and end users who rely on accurate authorship information for content management and security auditing purposes. The ability to spoof contributor-level or administrator-level authorship can be leveraged for social engineering attacks, where malicious events appear to originate from trusted users within the organization. This deception can lead to unauthorized access to sensitive information, as users may be more likely to trust content created by apparent contributors or administrators. Additionally, the vulnerability undermines audit trails and content management workflows, potentially causing confusion during incident response and security investigations where authorship attribution is critical.
The impact extends beyond simple deception to potentially enable more sophisticated attacks within WordPress environments, particularly when combined with other vulnerabilities or attack vectors. Security professionals should consider this vulnerability in the context of the ATT&CK framework, specifically under the T1078 Valid Accounts technique, where attackers leverage legitimate user accounts to perform malicious activities. The vulnerability also aligns with T1566 Impersonation tactics, as it enables attackers to impersonate higher-privileged users through calendar event manipulation. Organizations should implement immediate mitigations including updating to version 4.9.9 or later, implementing proper input validation for all user-supplied parameters, and conducting thorough security audits of plugin configurations to ensure that access controls are properly enforced across all content creation pathways.
Mitigation strategies should include immediate patching of the Spiffy Calendar plugin to version 4.9.9 or later, which addresses the specific authorization flaw in the event creation process. Administrators should also implement additional security measures such as monitoring for unauthorized changes to event authorship, enforcing strict input validation on all user-submitted data, and conducting regular security assessments of installed plugins. The vulnerability highlights the importance of proper access control implementation and demonstrates how seemingly minor oversight in parameter validation can create significant security risks within content management systems. Organizations should also consider implementing web application firewalls and security monitoring solutions that can detect and prevent unauthorized parameter manipulation attempts, while maintaining comprehensive logging of all content creation and modification activities to facilitate security investigations and compliance requirements.