CVE-2015-4148 in PHP
Summary
by MITRE
The do_soap_call function in ext/soap/soap.c in PHP before 5.4.39, 5.5.x before 5.5.23, and 5.6.x before 5.6.7 does not verify that the uri property is a string, which allows remote attackers to obtain sensitive information by providing crafted serialized data with an int data type, related to a "type confusion" issue.
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Analysis
by VulDB Data Team • 02/01/2025
The vulnerability identified as CVE-2015-4148 represents a critical type confusion flaw within PHP's SOAP extension that affects multiple version streams including 5.4.x before 5.4.39, 5.5.x before 5.5.23, and 5.6.x before 5.6.7. This issue resides in the do_soap_call function located within the ext/soap/soap.c source file, where the implementation fails to properly validate the data type of the uri property during SOAP operations. The flaw stems from inadequate input sanitization that allows malicious actors to exploit a type confusion vulnerability by manipulating serialized data structures. When PHP processes SOAP requests with crafted serialized data containing integer values instead of expected string values for the uri property, the application's type handling becomes compromised, creating potential avenues for information disclosure.
The technical exploitation of this vulnerability occurs through a sophisticated manipulation of PHP's serialization mechanism combined with SOAP protocol processing. Attackers can construct malicious serialized objects that contain an integer value where a string is expected for the uri property, leading to unpredictable behavior in the application's memory management and type handling. This type confusion creates a scenario where the application treats integer data as if it were string data, potentially causing memory corruption or information leakage. The vulnerability specifically leverages PHP's object serialization and deserialization processes, where the lack of proper type validation during SOAP communication allows attackers to inject malformed data that can be interpreted in unexpected ways by the underlying PHP engine.
The operational impact of CVE-2015-4148 extends beyond simple information disclosure to potentially enable more sophisticated attacks depending on the application context. Remote attackers can exploit this vulnerability to extract sensitive information from the application's memory space, including but not limited to database connection details, session tokens, or other confidential data that might be accessible through the SOAP interface. The vulnerability's classification aligns with CWE-129, which describes improper validation of the length or value of input data, and more specifically relates to CWE-704, which covers incorrect type handling in programming languages. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1059.007 for scripting languages and T1566 for malicious file execution, as it enables attackers to manipulate serialized data for information extraction purposes.
Mitigation strategies for this vulnerability require immediate patching of affected PHP versions to the officially released secure versions that address the type validation issue in the SOAP extension. Organizations should prioritize updating their PHP installations across all affected platforms, particularly those running web applications that utilize SOAP services. Additional defensive measures include implementing proper input validation at application level, sanitizing all SOAP request data before processing, and employing web application firewalls that can detect and block suspicious serialized data patterns. Security monitoring should focus on identifying unusual SOAP communication patterns and malformed serialized data that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper type checking in language implementations, particularly in extensions that handle complex data structures and external communication protocols, making it essential for developers to implement robust validation mechanisms and for organizations to maintain current security patch management processes.