CVE-2015-7695 in Zend
Summary
by MITRE
The PDO adapters in Zend Framework before 1.12.16 do not filer null bytes in SQL statements, which allows remote attackers to execute arbitrary SQL commands via a crafted query.
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Analysis
by VulDB Data Team • 01/08/2019
The vulnerability identified as CVE-2015-7695 affects the Zend Framework's PDO adapters and represents a critical SQL injection flaw that undermines database security controls. This weakness exists in versions prior to 1.12.16 and stems from insufficient input validation mechanisms within the framework's database abstraction layer. The core issue lies in the improper handling of null byte characters within SQL statements, creating an avenue for malicious actors to bypass normal query sanitization processes and inject arbitrary SQL commands directly into the database layer.
The technical exploitation of this vulnerability occurs when applications using affected Zend Framework versions process user-supplied input through PDO adapters without adequate filtering of null byte sequences. When a crafted query containing null bytes is submitted, the framework fails to properly sanitize these characters before passing the SQL statement to the underlying database engine. This failure creates a direct path for attackers to manipulate the intended query execution flow and potentially gain unauthorized access to database resources. The vulnerability specifically targets the data sanitization mechanisms within the PDO adapter implementation, where null byte filtering is either absent or insufficiently implemented.
From an operational perspective, this vulnerability poses significant risks to organizations relying on Zend Framework applications for database operations. Attackers can leverage this flaw to execute arbitrary SQL commands, potentially leading to data exfiltration, unauthorized data modification, complete database compromise, or even privilege escalation within the database environment. The remote nature of the attack means that adversaries do not require local system access or direct network connectivity to the database server itself, making the vulnerability particularly dangerous in web-facing applications. The impact extends beyond simple data theft as attackers may be able to manipulate database schema, create backdoor accounts, or execute administrative commands through the compromised application layer.
Organizations should prioritize immediate remediation by upgrading to Zend Framework version 1.12.16 or later, which includes proper null byte filtering mechanisms in the PDO adapters. Additional mitigations include implementing comprehensive input validation at multiple layers of the application architecture, deploying web application firewalls to detect and block suspicious SQL patterns, and conducting thorough code reviews to identify other potential injection points. Security teams should also implement monitoring for unusual database access patterns and establish robust database activity auditing to detect unauthorized command execution. This vulnerability aligns with CWE-77 and CWE-89 categories related to command injection and SQL injection respectively, and maps to ATT&CK technique T1071.004 for application layer protocol manipulation, highlighting the importance of proper input sanitization and the potential for lateral movement through database compromise.