CVE-2020-11534 : Exploit Details and Defense Strategies

An issue was discovered in ONLYOFFICE Document Server 5.5.0. An attacker can craft a malicious .docx file, and exploit the NSFileDownloader function to pass parameters to a binary (such as curl or wget) and remotely execute code on a victim's server.

Understanding CVE-2020-11534

This CVE involves a vulnerability in ONLYOFFICE Document Server 5.5.0 that allows remote code execution by manipulating a .docx file.

What is CVE-2020-11534?

The vulnerability in ONLYOFFICE Document Server 5.5.0 enables an attacker to execute arbitrary code on a target server by leveraging the NSFileDownloader function.

The Impact of CVE-2020-11534

Exploitation of this vulnerability can lead to unauthorized remote code execution on the victim's server, potentially causing data breaches and system compromise.

Technical Details of CVE-2020-11534

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The vulnerability allows attackers to embed malicious commands in a .docx file, exploiting the NSFileDownloader function to execute code remotely.

Affected Systems and Versions

ONLYOFFICE Document Server 5.5.0

Exploitation Mechanism

Craft a malicious .docx file with embedded commands
Exploit the NSFileDownloader function to execute remote code

Mitigation and Prevention

Protecting systems from CVE-2020-11534 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update ONLYOFFICE Document Server to the latest version
Implement strict file upload validation to prevent malicious files
Monitor network traffic for suspicious activities

Long-Term Security Practices

Conduct regular security audits and penetration testing
Educate users on safe file handling practices
Employ network segmentation to limit the impact of potential breaches

Patching and Updates

Apply patches and updates provided by ONLYOFFICE to address the vulnerability