CVE-2015-5467

Comprehensive Technical Analysis of CVE-2015-5467

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2015-5467 CVSS Score: 9.8

The vulnerability in question, CVE-2015-5467, affects the Yii framework (Yii2) versions before 2.0.5. The high CVSS score of 9.8 indicates a critical severity level. This vulnerability allows attackers to execute any local .php file by manipulating the view parameter with a relative path. This type of vulnerability is classified as a Local File Inclusion (LFI) vulnerability, which can lead to unauthorized code execution and potential compromise of the entire system.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Relative Path Manipulation: Attackers can exploit this vulnerability by crafting a URL that includes a relative path to a .php file. This can be done through various means such as web forms, URL parameters, or other user inputs that are not properly sanitized.
• Phishing and Social Engineering: Attackers may use phishing techniques to trick users into visiting a malicious URL that exploits this vulnerability.

Exploitation Methods:

• Direct Code Execution: By specifying a relative path to a .php file, attackers can execute arbitrary PHP code on the server. This can include commands to read sensitive files, execute system commands, or even upload additional malicious scripts.
• Chaining with Other Vulnerabilities: This LFI vulnerability can be chained with other vulnerabilities to escalate privileges or gain further access to the system.

3. Affected Systems and Software Versions

Affected Software:

• Yii (Yii2) versions before 2.0.5

Affected Systems:

• Any web application or server running the vulnerable versions of the Yii framework. This includes but is not limited to:
  • Web servers hosting applications built with Yii2.
  • Development and staging environments using Yii2.
  • Any system where Yii2 is integrated as part of a larger application stack.

4. Recommended Mitigation Strategies

Immediate Actions:

• Upgrade to a Secure Version: Upgrade to Yii2 version 2.0.5 or later, which includes the security fix for this vulnerability.
• Patch Management: Ensure that all systems and applications are regularly updated with the latest security patches.

Long-Term Strategies:

• Input Validation: Implement robust input validation and sanitization mechanisms to prevent relative path manipulation.
• Access Controls: Enforce strict access controls and permissions to limit the execution of arbitrary files.
• Monitoring and Logging: Implement comprehensive monitoring and logging to detect and respond to any suspicious activities.
• Security Audits: Conduct regular security audits and vulnerability assessments to identify and mitigate potential vulnerabilities.

5. Impact on Cybersecurity Landscape

The discovery and exploitation of CVE-2015-5467 highlight the critical importance of timely patch management and secure coding practices. This vulnerability underscores the risks associated with LFI vulnerabilities, which can lead to severe consequences such as data breaches, unauthorized access, and system compromise. The high CVSS score emphasizes the need for immediate action and the implementation of robust security measures to protect against similar vulnerabilities in the future.

6. Technical Details for Security Professionals

Vulnerability Details:

• Vulnerable Component: web\ViewAction in Yii2.
• Exploitation Mechanism: The view parameter is not properly sanitized, allowing attackers to specify a relative path to a .php file.
• Example Exploit: An attacker could craft a URL like http://example.com/index.php?r=site/view&view=../../../../etc/passwd, which could potentially read the /etc/passwd file if the server is configured to execute PHP code in this manner.

Mitigation Steps:

• Code Review: Conduct a thorough code review to identify and fix any instances where user input is not properly sanitized.
• Configuration Hardening: Ensure that the web server and PHP configurations are hardened to prevent the execution of arbitrary files.
• Web Application Firewall (WAF): Deploy a WAF to detect and block attempts to exploit this vulnerability.

Conclusion: CVE-2015-5467 is a critical vulnerability that requires immediate attention from cybersecurity professionals. By understanding the technical details and implementing the recommended mitigation strategies, organizations can protect their systems from potential exploitation and ensure a more secure cybersecurity landscape.