CVE-2016-10753 in e107
Summary
by MITRE
e107 2.1.2 allows PHP Object Injection with resultant SQL injection, because usersettings.php uses unserialize without an HMAC.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/24/2023
The vulnerability identified as CVE-2016-10753 affects the e107 content management system version 2.1.2 and represents a critical security flaw that combines PHP object injection with subsequent SQL injection capabilities. This vulnerability stems from improper input validation and sanitization within the usersettings.php script, which processes user data without adequate security measures to prevent malicious object deserialization. The flaw exists in the application's handling of serialized data, creating an exploitable path where attackers can manipulate serialized objects to execute arbitrary code.
The technical implementation of this vulnerability involves the use of PHP's unserialize() function in usersettings.php without proper HMAC (Hash-based Message Authentication Code) verification. When users submit data through the user settings interface, the system accepts serialized objects that are then unserialized without checking their integrity or authenticity. This creates a classic PHP object injection scenario where malicious actors can craft serialized objects containing malicious PHP code that gets executed during the unserialization process. The CWE-502 classification applies here as this represents a deserialization vulnerability that allows arbitrary code execution through the manipulation of serialized data structures.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with a pathway to achieve full system compromise. Once an attacker successfully injects malicious PHP objects, they can leverage the resulting code execution to perform SQL injection attacks against the underlying database, potentially extracting sensitive information, modifying user accounts, or even gaining shell access to the server. This vulnerability aligns with ATT&CK technique T1566.001 for initial access through malicious file execution, and T1071.004 for application layer protocol usage. The attack chain typically begins with exploiting the object injection vulnerability, followed by SQL injection to escalate privileges and access sensitive data.
The mitigation strategies for this vulnerability require immediate patching of the e107 CMS to version 2.1.3 or later, which includes proper HMAC verification for serialized data. Organizations should implement input validation and sanitization measures to prevent malicious serialized objects from being processed, and should consider implementing web application firewalls to detect and block suspicious serialization patterns. Additionally, security monitoring should be enhanced to detect unusual patterns in user settings submissions, and regular security audits should verify that all serialized data processing includes proper authentication mechanisms. The vulnerability demonstrates the critical importance of proper data validation and the dangers of using unserialize() without proper integrity checks, as highlighted in OWASP Top 10 2017 category A08: Insecure Deserialization.