CVE-2021-43281 Explained : Impact and Mitigation

MyBB before 1.8.29 allows Remote Code Injection by an admin with the "Can manage settings?" permission. Learn about the impact, technical details, and mitigation steps for this CVE.

Understanding CVE-2021-43281

MyBB before version 1.8.29 is vulnerable to Remote Code Injection through the Admin CP's Settings management module.

What is CVE-2021-43281?

This CVE allows an admin with specific permissions to inject PHP code via Settings, leading to code execution.

The Impact of CVE-2021-43281

The vulnerability enables malicious admins to execute PHP code within the Admin CP, potentially leading to unauthorized system access.

Technical Details of CVE-2021-43281

MyBB's version before 1.8.29 is subject to this remote code injection vulnerability.

Vulnerability Description

The Settings management module fails to properly validate certain setting types, allowing the addition of PHP settings for code execution.

Affected Systems and Versions

Product: MyBB
Version: < 1.8.29

Exploitation Mechanism

Admins with the "Can manage settings?" permission can exploit this issue by inserting PHP code in supported setting types.

Mitigation and Prevention

Immediate action is crucial to prevent exploitation and maintain system security.

Immediate Steps to Take

Upgrade MyBB to version 1.8.29 or later to patch the vulnerability.
Monitor admin actions for suspicious activities.

Long-Term Security Practices

Regularly review and update admin permissions.
Conduct security training for administrators to raise awareness of potential threats.

Patching and Updates

Stay informed about security advisories and promptly apply patches to mitigate risks.