CVE-2015-4601 in PHP
Summary
by MITRE
PHP before 5.6.7 might allow remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via an unexpected data type, related to "type confusion" issues in (1) ext/soap/php_encoding.c, (2) ext/soap/php_http.c, and (3) ext/soap/soap.c, a different issue than CVE-2015-4600.
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Analysis
by VulDB Data Team • 05/22/2022
The vulnerability identified as CVE-2015-4601 represents a critical type confusion issue affecting PHP versions prior to 5.6.7, specifically within the SOAP extension modules. This flaw stems from improper handling of data types during SOAP message processing, creating opportunities for remote attackers to manipulate application behavior through crafted input sequences. The vulnerability manifests in three distinct files within the SOAP extension: ext/soap/php_encoding.c, ext/soap/php_http.c, and ext/soap/soap.c, each representing different layers of SOAP protocol handling where type confusion can occur. The root cause lies in PHP's inability to properly validate and manage data type transitions during SOAP message deserialization, leading to potential memory corruption and arbitrary code execution.
The technical implementation of this vulnerability exploits fundamental type confusion patterns that fall under CWE-479, which specifically addresses the use of a function with an incorrect number of arguments or incorrect argument types. When PHP processes SOAP messages, it attempts to deserialize complex data structures containing mixed data types, but fails to properly validate the expected types during this process. Attackers can craft malicious SOAP requests containing specially formatted data that causes PHP's internal type handling mechanisms to misinterpret data structures, leading to memory corruption. This type confusion can result in stack corruption, heap corruption, or other memory management issues that ultimately manifest as application crashes or provide attackers with opportunities to execute arbitrary code on the target system.
The operational impact of CVE-2015-4601 extends beyond simple denial of service scenarios, as the vulnerability can potentially enable remote code execution depending on the specific conditions and memory layout during exploitation. Systems running vulnerable PHP versions that process SOAP requests are particularly at risk, especially web applications that utilize SOAP web services or SOAP client functionality. The vulnerability affects any PHP application that relies on the SOAP extension for web service communication, making it particularly dangerous in enterprise environments where SOAP-based APIs are commonly used for integration between systems. The attack surface includes not only direct web applications but also any service that accepts SOAP input from untrusted sources, including API gateways, middleware systems, and service orchestrators that process SOAP messages.
Organizations should prioritize immediate patching of PHP installations to versions 5.6.7 or later, as this vulnerability represents a significant risk to system integrity and availability. The remediation process should include comprehensive testing of SOAP-based applications to ensure that the patch does not introduce regressions in existing functionality. Security teams should implement network segmentation to limit exposure of systems running vulnerable PHP versions and consider deploying web application firewalls to monitor and filter suspicious SOAP traffic. Additionally, organizations should conduct thorough vulnerability assessments of their SOAP-based web services to identify potential attack vectors and implement proper input validation and sanitization measures. The ATT&CK framework categorizes this vulnerability under T1203 - Exploitation for Client Execution and T1499 - Endpoint Termination, emphasizing the need for both defensive measures and incident response planning. Regular security monitoring should be implemented to detect potential exploitation attempts, and system administrators should maintain detailed logs of SOAP service interactions for forensic analysis purposes.