CVE-2014-8998 in X7 Chat
Summary
by MITRE
lib/message.php in X7 Chat 2.0.0 through 2.0.5.1 allows remote authenticated users to execute arbitrary PHP code via a crafted HTTP header to index.php, which is processed by the preg_replace function with the eval switch.
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability identified as CVE-2014-8998 resides within the X7 Chat messaging platform version 2.0.0 through 2.0.5.1, specifically in the lib/message.php file. This represents a critical security flaw that enables remote authenticated attackers to execute arbitrary PHP code through manipulation of HTTP headers. The vulnerability exploits the application's improper handling of user-supplied input within the preg_replace function, which is configured to use the eval switch, creating a dangerous execution path for malicious payloads.
The technical flaw stems from the application's reliance on user-provided HTTP header data without adequate sanitization or validation before processing through the preg_replace function. When a crafted HTTP header is sent to the index.php endpoint, the application processes this input through a vulnerable preg_replace operation that includes the eval modifier. This modifier allows the regular expression pattern to be executed as PHP code, effectively transforming what should be harmless header data into a vehicle for code execution. The vulnerability operates under CWE-94, which classifies it as an "Improper Control of Generation of Code ('Code Injection')" due to the application's failure to properly control code generation from external inputs.
The operational impact of this vulnerability is severe and far-reaching for any system running the affected X7 Chat versions. An authenticated attacker who can manipulate HTTP headers gains the ability to execute arbitrary PHP commands on the server, potentially leading to complete system compromise. This access could enable attackers to read sensitive data, modify system files, establish persistent backdoors, or use the compromised server for further attacks against other systems. The vulnerability affects the confidentiality, integrity, and availability of the affected system, making it a critical concern for organizations relying on this messaging platform.
The attack vector for this vulnerability requires an authenticated user, which slightly reduces the attack surface compared to unauthenticated exploits, but still represents a significant risk as it allows for privilege escalation and lateral movement within the system. According to ATT&CK framework, this vulnerability maps to T1059.007 for "Command and Scripting Interpreter: PowerShell" and T1059.001 for "Command and Scripting Interpreter: Python," as the exploitation involves executing command-line or scripting language code. Organizations should implement immediate mitigations including upgrading to a patched version of X7 Chat, implementing proper input validation and sanitization, and monitoring for suspicious HTTP header patterns. The recommended remediation strategy involves applying the vendor's security patch, which typically addresses the improper use of preg_replace with eval modifier, and implementing web application firewalls to detect and block malicious header manipulation attempts.