CVE-2021-20769 : Exploit Details and Defense Strategies

This article provides detailed information about CVE-2021-20769, a cross-site scripting vulnerability in Cybozu Garoon versions 4.6.0 to 5.0.2 that allows a remote authenticated attacker to inject arbitrary scripts.

Understanding CVE-2021-20769

Cybozu Garoon versions 4.6.0 to 5.0.2 are affected by a cross-site scripting vulnerability that can be exploited by a remote authenticated attacker to execute arbitrary scripts.

What is CVE-2021-20769?

CVE-2021-20769 is a security vulnerability in the bulletin feature of Cybozu Garoon versions 4.6.0 to 5.0.2, which enables a remote authenticated attacker to inject malicious scripts through unspecified vectors.

The Impact of CVE-2021-20769

The vulnerability poses a risk of unauthorized script injection by attackers with authenticated access, potentially leading to data theft, unauthorized actions, or further exploitation of the affected system.

Technical Details of CVE-2021-20769

Cybozu Garoon versions 4.6.0 to 5.0.2 are prone to a cross-site scripting flaw that arises from inadequate input validation in the bulletin module.

Vulnerability Description

The cross-site scripting vulnerability in Cybozu Garoon versions 4.6.0 to 5.0.2 allows attackers to inject arbitrary scripts into bulletin content, which can then be executed within the context of a user's web browser.

Affected Systems and Versions

Cybozu Garoon versions 4.6.0 to 5.0.2 are confirmed to be affected by this vulnerability, leaving systems with these versions at risk of exploit.

Exploitation Mechanism

Exploitation of CVE-2021-20769 requires an attacker to be authenticated, allowing them to craft and submit malicious scripts through the bulletin functionality, subsequently affecting other users who view the compromised content.

Mitigation and Prevention

To mitigate the risks associated with CVE-2021-20769, immediate actions and long-term security practices need to be implemented.

Immediate Steps to Take

Users are urged to update Cybozu Garoon to a patched version or apply vendor-supplied fixes. Additionally, exercise caution while interacting with bulletin content to avoid executing malicious scripts.

Long-Term Security Practices

Implement regular security assessments, educate users on safe browsing practices, and maintain an incident response plan to address security incidents promptly.

Patching and Updates

Cybozu, Inc. has released fixes for Cybozu Garoon to address CVE-2021-20769. Users should apply the latest patches and updates provided by the vendor to eliminate the vulnerability.