CVE-2021-21799 : Exploit Details and Defense Strategies

This article provides details about CVE-2021-21799, a critical cross-site scripting vulnerability affecting Advantech R-SeeNet 2.4.12 (20.10.2020).

Understanding CVE-2021-21799

CVE-2021-21799 is a critical vulnerability that exists in the telnet_form.php script functionality of Advantech R-SeeNet v 2.4.12 (20.10.2020). If exploited, it allows an attacker to execute arbitrary JavaScript code in the targeted user's browser.

What is CVE-2021-21799?

CVE-2021-21799 is a cross-site scripting vulnerability that can be triggered when a user visits a specially crafted URL. This can lead to the execution of malicious scripts in the context of the user's browser.

The Impact of CVE-2021-21799

With a CVSS base score of 9.6 (Critical), this vulnerability has a high impact on confidentiality, integrity, and availability. An attacker exploiting this issue can perform arbitrary code execution in the user's browser.

Technical Details of CVE-2021-21799

The following technical details describe the vulnerability in more depth:

Vulnerability Description

The cross-site scripting vulnerability in Advantech R-SeeNet allows attackers to execute arbitrary JavaScript code via a specially crafted URL.

Affected Systems and Versions

Advantech R-SeeNet 2.4.12 (20.10.2020) is affected by this vulnerability.

Exploitation Mechanism

By enticing a user to click on a malicious URL, an attacker can trigger the execution of arbitrary scripts within the user's browser.

Mitigation and Prevention

To mitigate the risks associated with CVE-2021-21799, consider the following steps:

Immediate Steps to Take

Users are advised to avoid clicking on untrusted or suspicious links to prevent exploitation of this vulnerability.

Long-Term Security Practices

Implementing secure coding practices and regular security audits can help prevent cross-site scripting vulnerabilities.

Patching and Updates

Ensure that Advantech R-SeeNet is updated to the latest version that addresses this vulnerability.