CVE-2022-24979 in Varnishcache
Summary
by MITRE • 02/19/2022
An issue was discovered in the Varnishcache extension before 2.0.1 for TYPO3. The Edge Site Includes (ESI) content element renderer component does not include an access check. This allows an unauthenticated user to render various content elements, resulting in insecure direct object reference (IDOR), with the potential of exposing internal content elements.
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Analysis
by VulDB Data Team • 02/19/2022
The vulnerability identified in the Varnishcache extension for TYPO3 represents a critical access control flaw that undermines the security posture of web applications relying on this caching solution. This issue affects versions prior to 2.0.1 and specifically targets the Edge Site Includes content element renderer component, which is designed to facilitate dynamic content inclusion in edge caching scenarios. The absence of proper authentication and authorization checks within this component creates a pathway for unauthorized access to protected content elements that should only be accessible to authenticated users with appropriate permissions.
The technical implementation flaw stems from the Edge Site Includes functionality failing to validate user credentials or session state before rendering content elements. This design oversight allows any unauthenticated attacker to exploit the ESI rendering mechanism to access internal content that would normally be restricted. The vulnerability manifests as an insecure direct object reference condition where the system directly references internal resources without proper access validation. This type of vulnerability is categorized under CWE-284 Access Control Issues and aligns with ATT&CK technique T1078 Valid Accounts, as it enables unauthorized access through legitimate system interfaces without requiring additional credential compromise.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with access to internal content elements that may contain sensitive data, system configurations, or administrative interfaces. When combined with other reconnaissance activities, this vulnerability can enable attackers to map internal application structures and identify additional attack vectors. The exposure of internal content elements through ESI rendering creates opportunities for further exploitation including potential data leakage, privilege escalation, or the discovery of additional system components that may be vulnerable to other attack techniques. The vulnerability affects the core caching functionality of TYPO3 installations that utilize Varnishcache, potentially compromising the security of entire web applications that depend on this extension for performance optimization.
Mitigation strategies should focus on implementing proper access controls within the ESI rendering component, including mandatory authentication checks and authorization validation before content element rendering. Organizations should immediately upgrade to Varnishcache extension version 2.0.1 or later, which addresses this vulnerability through proper access control implementation. Additionally, security teams should conduct comprehensive audits of all content rendering components to identify similar access control gaps, implement proper logging and monitoring of content access patterns, and ensure that all user sessions are properly validated before content rendering occurs. The fix should incorporate principle of least privilege concepts and follow secure coding practices that prevent direct object references without proper access validation, aligning with ATT&CK mitigations for credential access and privilege escalation techniques.