CVE-2021-28846 Explained : Impact and Mitigation
Learn about CVE-2021-28846, a Format String vulnerability in TRENDnet TEW-755AP, TEW-821DAP2KAC, and TEW-825DAP devices, allowing remote attackers to trigger a denial of service.
A Format String vulnerability exists in TRENDnet TEW-755AP 1.11B03, TEW-755AP2KAC 1.11B03, TEW-821DAP2KAC 1.11B03, and TEW-825DAP 1.11B03, which could allow a remote malicious user to cause a denial of service. The vulnerability arises due to a logic bug when calling fprintf with a specific format, potentially leading to a denial of service attack.
Understanding CVE-2021-28846
This section will delve into what CVE-2021-28846 is, the impact it poses, technical details, and mitigation steps.
What is CVE-2021-28846?
CVE-2021-28846 is a Format String vulnerability present in multiple TRENDnet devices that can be exploited by a remote attacker to disrupt services by leveraging a logic bug.
The Impact of CVE-2021-28846
The vulnerability could be triggered by an attacker sending a POST request with a long and unknown key in the request body, potentially leading to a denial of service.
Technical Details of CVE-2021-28846
Let's explore the specific technical details of the vulnerability.
Vulnerability Description
The vulnerability exists in the way fprintf function is called, with two variables being incorrectly ordered in the format string, creating an opportunity for exploitation.
Affected Systems and Versions
TRENDnet TEW-755AP 1.11B03, TEW-755AP2KAC 1.11B03, TEW-821DAP2KAC 1.11B03, and TEW-825DAP 1.11B03 are known to be affected by this vulnerability.
Exploitation Mechanism
The vulnerability can be exploited by sending a POST request to apply_cgi with a carefully crafted long and unknown key in the request body.
Mitigation and Prevention
Here, we'll cover the steps to mitigate and prevent the exploitation of CVE-2021-28846.
Immediate Steps to Take
It's recommended to apply security patches provided by TRENDnet to address the vulnerability.
Long-Term Security Practices
Implement network segmentation and access controls to minimize the attack surface and regularly update firmware to protect against known vulnerabilities.
Patching and Updates
Stay informed about security advisories from TRENDnet and apply patches promptly to ensure the security of the affected devices.