CVE-2021-42654 : Exploit Details and Defense Strategies

SiteServer CMS < V5.1 is affected by an unrestricted upload of a file with dangerous type (getshell), leading to the execution of arbitrary code.

Understanding CVE-2021-42654

SiteServer CMS < V5.1 is susceptible to a file upload vulnerability that could allow attackers to execute arbitrary code.

What is CVE-2021-42654?

The vulnerability in SiteServer CMS < V5.1 allows malicious users to upload a file with a dangerous type, ultimately enabling the execution of arbitrary code on the system.

The Impact of CVE-2021-42654

This vulnerability can result in unauthorized execution of arbitrary code by attackers, potentially leading to complete compromise of the affected system.

Technical Details of CVE-2021-42654

SiteServer CMS < V5.1 has the following technical details:

Vulnerability Description

The vulnerability involves an unrestricted file upload issue that permits the uploading of files with malicious content, posing a significant risk of arbitrary code execution.

Affected Systems and Versions

SiteServer CMS versions prior to V5.1

Exploitation Mechanism

Attackers can exploit this vulnerability by uploading a file with a dangerous type, such as a PHP shell script, through the affected application.

Mitigation and Prevention

To address CVE-2021-42654, take the following steps:

Immediate Steps to Take

Implement input validation routines to restrict file types that can be uploaded.
Monitor file upload activities for suspicious patterns.
Apply web application firewalls to filter out malicious file uploads.

Long-Term Security Practices

Regularly update SiteServer CMS to the latest version to patch known vulnerabilities.
Conduct security audits and penetration testing to identify and address any security weaknesses.

Patching and Updates

Ensure timely installation of security patches provided by SiteServer CMS to mitigate the vulnerability.