CVE-2016-7417 in macOS
Summary
by MITRE
ext/spl/spl_array.c in PHP before 5.6.26 and 7.x before 7.0.11 proceeds with SplArray unserialization without validating a return value and data type, which allows remote attackers to cause a denial of service or possibly have unspecified other impact via crafted serialized data.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/07/2022
The vulnerability identified as CVE-2016-7417 resides within the PHP scripting language's Standard PHP Library implementation, specifically in the spl_array.c file that handles SplArray object serialization and unserialization processes. This flaw affects PHP versions prior to 5.6.26 and 7.0.11, representing a critical security weakness that could be exploited by remote attackers to compromise system availability and potentially execute arbitrary code. The vulnerability stems from inadequate input validation during the unserialization phase, where the system fails to properly validate return values and data types before proceeding with object reconstruction.
The technical nature of this vulnerability involves a lack of proper validation checks during the unserialize operation of SplArray objects, which creates opportunities for attackers to craft malicious serialized data that can trigger unexpected behavior in the PHP interpreter. When PHP attempts to unserialize a malicious SplArray object, the system processes the data without sufficient type checking or return value validation, leading to potential memory corruption or execution flow manipulation. This flaw operates at the core level of PHP's object handling mechanisms, making it particularly dangerous as it can be leveraged to bypass normal security controls and potentially escalate privileges.
From an operational perspective, this vulnerability presents significant risks to web applications that utilize PHP and handle user-supplied serialized data. Attackers can exploit this weakness to cause denial of service conditions by crafting serialized data that triggers memory exhaustion or infinite loops during unserialization. The potential impact extends beyond simple service disruption, as the improper validation could enable more sophisticated attacks depending on the system configuration and available attack surface. Organizations running affected PHP versions face substantial risk of system compromise, data loss, and unauthorized access to their web applications and underlying infrastructure.
The mitigation strategy for CVE-2016-7417 primarily involves upgrading to PHP versions 5.6.26 or 7.0.11 and later, which contain the necessary patches to properly validate return values and data types during SplArray unserialization. System administrators should also implement strict input validation policies for any user-supplied serialized data, particularly when processing data from untrusted sources. Security monitoring should be enhanced to detect unusual patterns in serialization operations, and regular security assessments should be conducted to identify potential exploitation attempts. This vulnerability aligns with CWE-248, which addresses "Uncaught Exception" conditions, and maps to ATT&CK technique T1203, "Exploitation for Client Execution," as it represents a remote code execution vector through serialized object manipulation. Organizations should also consider implementing web application firewalls and input sanitization measures to provide additional defense-in-depth against similar serialization-based attacks that could exploit similar weaknesses in other components of their PHP applications.