CVE-2018-11772 in Apache VCL
Summary
by MITRE
Apache VCL versions 2.1 through 2.5 do not properly validate cookie input when determining what node (if any) was previously selected in the privilege tree. The cookie data is then used in an SQL statement. This allows for an SQL injection attack. Access to this portion of a VCL system requires admin level rights. Other layers of security seem to protect against malicious attack. However, all VCL systems running versions earlier than 2.5.1 should be upgraded or patched. This vulnerability was found and reported to the Apache VCL project by ADLab of Venustech.
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Analysis
by VulDB Data Team • 07/15/2020
The vulnerability described in CVE-2018-11772 represents a critical SQL injection flaw within Apache VCL versions 2.1 through 2.5, specifically affecting the privilege tree node selection functionality. This vulnerability resides in the cookie validation mechanism that determines previously selected nodes within the system's privilege hierarchy, creating an exploitable path for malicious actors to manipulate database queries through crafted cookie inputs.
The technical implementation of this vulnerability stems from insufficient input validation within the cookie processing logic of the VCL system. When administrators interact with the privilege tree interface, the system stores node selection information in cookies for subsequent sessions. However, the application fails to properly sanitize or validate this cookie data before incorporating it into SQL statements, directly exposing the database layer to injection attacks. This weakness falls under CWE-89 which specifically addresses SQL injection vulnerabilities where untrusted data is directly included in database queries without proper sanitization.
The operational impact of this vulnerability is significant despite requiring administrative privileges for exploitation, as it provides a direct path to database manipulation and potential data compromise. The attack vector involves crafting malicious cookie values that, when processed by the vulnerable application, result in malformed SQL queries that can be leveraged to extract, modify, or delete sensitive data from the underlying database. This represents a privilege escalation scenario where authenticated administrators could potentially exploit this weakness to gain deeper access to system resources beyond their intended administrative scope.
The security implications extend beyond simple data theft, as successful exploitation could enable attackers to manipulate the privilege structure itself, potentially allowing them to elevate their access rights or create backdoor accounts within the VCL environment. The vulnerability's discovery by ADLab of Venustech highlights the importance of third-party security assessments in identifying such critical flaws that may not be immediately apparent through standard development processes. Organizations running affected versions should prioritize immediate patching to version 2.5.1 or later, as this represents the first fixed release that properly addresses the cookie validation weakness. The vulnerability demonstrates the critical nature of input validation in web applications and underscores the necessity of implementing proper parameterized queries to prevent SQL injection attacks. This case also illustrates how layered security approaches, while providing additional protection, cannot fully compensate for fundamental validation flaws in core application components, making timely patch management essential for maintaining system integrity.