CVE-2021-21967 : Vulnerability Insights and Analysis

This article provides detailed information about CVE-2021-21967, a vulnerability affecting SeaConnect 370W devices by Sealevel Systems, Inc.

Understanding CVE-2021-21967

CVE-2021-21967 is an out-of-bounds write vulnerability in the OTA update task functionality of SeaConnect 370W v1.3.34. It can be exploited by a specially-crafted MQTT payload, potentially leading to a denial of service. Attackers can trigger this vulnerability through a man-in-the-middle attack.

What is CVE-2021-21967?

CVE-2021-21967 is a high-risk vulnerability in Sealevel Systems, Inc. SeaConnect 370W v1.3.34 that allows an attacker to perform a denial of service attack through malicious MQTT payloads.

The Impact of CVE-2021-21967

The vulnerability's impact is rated as medium severity with a CVSS base score of 6.5. It poses a high availability impact, medium integrity impact, and low confidentiality impact. No user interaction or special privileges are required for exploitation.

Technical Details of CVE-2021-21967

This section covers the technical aspects of CVE-2021-21967, including a description of the vulnerability, affected systems and versions, and the exploitation mechanism.

Vulnerability Description

CVE-2021-21967 is categorized as CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow'). It arises in the OTA update task function of SeaConnect 370W v1.3.34, allowing unauthorized write access beyond the bounds of allocated memory.

Affected Systems and Versions

The vulnerability affects Sealevel Systems, Inc. SeaConnect 370W devices running version v1.3.34.

Exploitation Mechanism

By sending a specially-crafted MQTT payload, an attacker can trigger the out-of-bounds write vulnerability, leading to denial of service conditions via a man-in-the-middle attack.

Mitigation and Prevention

To mitigate the risks associated with CVE-2021-21967, immediate steps should be taken along with adopting long-term security practices and applying necessary patches and updates.

Immediate Steps to Take

Organizations are advised to implement network protections, such as firewalls and intrusion detection systems, to monitor and restrict MQTT traffic. Additionally, considering network segmentation and access controls can limit the attack surface.

Long-Term Security Practices

Regular security assessments, employee training on cybersecurity best practices, and ensuring timely software updates are essential to maintain a secure environment and prevent potential vulnerabilities.

Patching and Updates

Sealevel Systems, Inc. should release a patch addressing CVE-2021-21967 promptly. Organizations using SeaConnect 370W v1.3.34 should apply the patch as soon as it becomes available to eliminate the vulnerability.