CVE-2016-8899 in Exponent
Summary
by MITRE
Exponent CMS version 2.3.9 suffers from a Object Injection vulnerability in framework/modules/core/controllers/expCatController.php related to change_cats.
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Analysis
by VulDB Data Team • 09/24/2023
The vulnerability identified as CVE-2016-8899 affects Exponent CMS version 2.3.9 and represents a critical object injection flaw within the core framework components. This vulnerability exists in the expCatController.php file where the change_cats functionality processes user input without adequate sanitization or validation mechanisms. The flaw allows attackers to inject malicious objects into the application's processing pipeline, potentially enabling arbitrary code execution or data manipulation within the CMS environment.
The technical implementation of this vulnerability stems from improper handling of serialized data within the controller's change_cats method. When users interact with the category management functionality, the application accepts input that should be processed through safe serialization and deserialization routines. However, the lack of proper input validation and sanitization creates an attack surface where maliciously crafted serialized objects can be executed within the application context. This pattern aligns with CWE-502 which specifically addresses deserialization of untrusted data as a primary attack vector for object injection vulnerabilities.
The operational impact of this vulnerability extends beyond simple data corruption or unauthorized access. An attacker who successfully exploits this vulnerability could potentially achieve complete system compromise by injecting malicious objects that execute within the CMS environment. The attack surface is particularly concerning as it affects core category management functionality that is likely accessed by administrators and content creators with elevated privileges. This could lead to unauthorized content modification, data exfiltration, or even persistent backdoor establishment within the CMS infrastructure.
The vulnerability demonstrates a fundamental flaw in the application's security architecture where input validation occurs too late in the processing chain or not at all. The attack vector requires minimal privileges as the vulnerability exists within the core framework rather than requiring specific administrative access. This makes the vulnerability particularly dangerous as it can be exploited by attackers with basic access to the CMS interface. The impact is further amplified by the fact that CMS platforms often contain sensitive organizational data and serve as central points for content management and user authentication.
Security mitigations for this vulnerability should focus on immediate patching of the Exponent CMS to version 2.3.10 or later where the object injection flaw has been addressed. Additionally, implementing proper input validation and sanitization measures within the application's core framework is essential. Organizations should also consider implementing web application firewalls with rules specifically designed to detect and block suspicious serialized object patterns. The remediation process should include thorough code review of similar patterns throughout the application's codebase to identify and address potential similar vulnerabilities. This vulnerability exemplifies the importance of following secure coding practices as outlined in the OWASP Top Ten and aligns with ATT&CK techniques related to deserialization attacks and privilege escalation through application flaws.