CVE-2016-3953 in Web2py
Summary
by MITRE
The sample web application in web2py before 2.14.2 might allow remote attackers to execute arbitrary code via vectors involving use of a hardcoded encryption key when calling the session.connect function.
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Analysis
by VulDB Data Team • 02/03/2023
The vulnerability identified as CVE-2016-3953 resides within the web2py framework version 2.14.1 and earlier, presenting a critical security risk through improper cryptographic implementation in session management. This flaw specifically affects the session.connect function which utilizes a hardcoded encryption key, creating a pathway for remote attackers to exploit the system and execute arbitrary code on the affected server. The vulnerability stems from the framework's default configuration where a static encryption key is embedded within the application code, making it predictable and exploitable by malicious actors who can leverage this weakness to gain unauthorized access to the system.
The technical exploitation of this vulnerability occurs through the manipulation of session data that relies on the hardcoded encryption key for validation and decryption processes. When web2py applications utilize the session.connect function without proper key management, attackers can craft malicious session data that bypasses authentication mechanisms and allows for arbitrary code execution. This represents a direct violation of cryptographic best practices and falls under the CWE-327 weakness category, specifically addressing the use of insecure cryptographic algorithms and the exposure of cryptographic keys. The hardcoded nature of the encryption key eliminates any form of dynamic key generation or secure key storage mechanisms, making the system inherently vulnerable to attack.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete control over the affected web server and potentially the underlying infrastructure. Remote code execution capabilities enable adversaries to install backdoors, exfiltrate sensitive data, modify application behavior, and establish persistent access to the system. The implications are particularly severe for web applications that handle sensitive information or serve as critical business services, as the vulnerability can be exploited without requiring authentication or prior access to the system. This aligns with ATT&CK technique T1059 which describes the use of remote code execution capabilities to gain system access and maintain persistence.
Organizations using web2py versions prior to 2.14.2 face significant security risks that require immediate remediation. The recommended mitigation strategy involves upgrading to web2py version 2.14.2 or later, which addresses the hardcoded encryption key issue through proper cryptographic key management and dynamic key generation. Additionally, system administrators should implement proper session management configurations, regularly audit encryption key usage, and consider implementing network segmentation to limit the potential impact of successful exploitation. The vulnerability demonstrates the critical importance of following secure coding practices and proper cryptographic implementation, as outlined in industry standards such as NIST SP 800-57 for cryptographic key management and OWASP Top Ten for web application security controls. Organizations should also conduct comprehensive security assessments to identify any other instances of hardcoded credentials or encryption keys within their applications and infrastructure.