CVE-2020-5256 Explained : Impact and Mitigation

BookStack before version 0.25.5 allows users to upload PHP files through image upload functions, leading to remote code execution with PHP process permissions.

Understanding CVE-2020-5256

BookStack vulnerability allowing remote code execution through image uploads.

What is CVE-2020-5256?

BookStack < 0.25.5 permits uploading PHP files via image upload functions, enabling remote code execution.
Attackers can execute code on the host system with PHP process permissions.
Most critical when non-trusted users can upload images in any application area.

The Impact of CVE-2020-5256

CVSS Score: 7.9 (High Severity)
Attack Complexity: High
Attack Vector: Network
Confidentiality, Integrity, and Privileges Impact: High
Scope: Changed, User Interaction Required

Technical Details of CVE-2020-5256

BookStack vulnerability details and affected systems.

Vulnerability Description

Users can upload PHP files through image upload functions, leading to remote code execution.

Affected Systems and Versions

Product: BookStack
Vendor: BookStackApp
Versions Affected: < 0.25.5

Exploitation Mechanism

Attackers exploit image upload functions to upload PHP files and execute code remotely.

Mitigation and Prevention

Protecting systems from CVE-2020-5256.

Immediate Steps to Take

Upgrade BookStack to at least version 0.25.5 to mitigate the vulnerability.

Long-Term Security Practices

Restrict image upload permissions to trusted users only.
Regularly monitor and audit uploaded files for malicious content.
Educate users on safe file upload practices.

Patching and Updates

Apply patches released in versions 0.25.3, 0.25.4, and 0.25.5 to address the vulnerability.