CVE-2017-5358 in EasyCom
Summary
by MITRE
Stack-based buffer overflows in php_Easycom5_3_0.dll in EasyCom for PHP 4.0.0.29 allows remote attackers to execute arbitrary code via the server argument to the (1) i5_connect, (2) i5_pconnect, or (3) i5_private_connect API function.
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Analysis
by VulDB Data Team • 12/03/2025
The vulnerability identified as CVE-2017-5358 represents a critical stack-based buffer overflow flaw within the php_Easycom5_3_0.dll library component of EasyCom for PHP version 4.0.0.29. This vulnerability exists in the form of improper input validation and memory management within the EasyCom PHP extension that handles IBM iSeries database connections. The flaw manifests when the extension processes server arguments through three specific API functions: i5_connect, i5_pconnect, and i5_private_connect, which are designed to establish connections to IBM iSeries systems. The buffer overflow occurs because the extension fails to properly validate the length of input data passed to these functions, allowing attackers to overwrite adjacent memory locations on the stack. This vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental memory safety issue that has been consistently identified as one of the most dangerous classes of vulnerabilities in software security.
The operational impact of this vulnerability is severe and directly enables remote code execution capabilities for attackers who can successfully exploit the buffer overflow condition. When an attacker provides a maliciously crafted server argument that exceeds the allocated buffer size, the overflow corrupts the stack memory, potentially allowing the execution of arbitrary code with the privileges of the affected web application process. This means that an attacker could gain full control over the web server hosting the vulnerable PHP application, potentially leading to complete system compromise, data exfiltration, or use of the compromised server for further attacks within the network. The vulnerability is particularly dangerous because it requires no local access or authentication, making it a classic remote exploitation vector that can be triggered through web-based attacks against exposed PHP applications using the EasyCom extension.
The attack surface for this vulnerability extends to any web application that utilizes the EasyCom for PHP extension and exposes functions that accept user-provided server arguments through the affected API endpoints. Organizations running vulnerable PHP applications on web servers that are accessible from the internet face significant risk, especially those that use IBM iSeries database connectivity features. The vulnerability's exploitation is facilitated by the fact that the affected functions are commonly used in web applications for database connection management, and the buffer overflow occurs during the initial connection establishment phase. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1203 Exploitation for Client Execution, where attackers leverage remote code execution vulnerabilities to gain control over target systems. Security professionals should note that the vulnerability's impact is amplified in environments where the web application runs with elevated privileges or where the database connection is used for sensitive operations.
Mitigation strategies for CVE-2017-5358 should begin with immediate patching of the affected EasyCom for PHP extension to version 4.0.0.30 or later, which contains the necessary fixes for the buffer overflow conditions. Organizations should also implement network segmentation to limit access to web applications using the vulnerable extension, particularly by restricting access to internal networks where possible. Input validation controls should be strengthened at the application level to ensure that all server arguments passed to the affected API functions are properly sanitized and bounded. Security monitoring should be enhanced to detect unusual patterns in database connection attempts that might indicate exploitation attempts. Additionally, organizations should consider implementing runtime protection mechanisms such as stack canaries or address space layout randomization to make exploitation more difficult. The vulnerability highlights the importance of regular security assessments of third-party PHP extensions and maintaining up-to-date software versions to prevent exploitation of known vulnerabilities that could lead to complete system compromise.