CVE-2021-31366 Explained : Impact and Mitigation
Get detailed insights into CVE-2021-31366, an Unchecked Return Value vulnerability in Juniper Networks Junos OS on MX Series. Learn about the impact, affected systems, and mitigation steps.
An Unchecked Return Value vulnerability in the authd (authentication daemon) of Juniper Networks Junos OS on MX Series configured for subscriber management / BBE allows an adjacent attacker to cause a crash by sending a specific username. This impacts authentication, authorization, and accounting (AAA) services on the MX devices and leads to a Denial of Service (DoS) condition. Continued receipt of these PPP login requests will create a sustained Denial of Service (DoS) condition.
Understanding CVE-2021-31366
This vulnerability affects Juniper Networks Junos OS on MX Series devices, potentially leading to a Denial of Service (DoS) condition.
What is CVE-2021-31366?
CVE-2021-31366 is an Unchecked Return Value vulnerability in the authentication daemon of Juniper Networks Junos OS, allowing an adjacent attacker to crash the system by sending a specific username.
The Impact of CVE-2021-31366
The vulnerability impacts authentication, authorization, and accounting services on affected Junos OS versions, resulting in a Denial of Service (DoS) situation when processing malicious login attempts.
Technical Details of CVE-2021-31366
This section provides deeper insights into the specific details of the vulnerability.
Vulnerability Description
The vulnerability arises due to an Unchecked Return Value issue in the authd service, enabling a crash triggered by a malicious username.
Affected Systems and Versions
The affected systems include Juniper Networks Junos OS versions prior to 15.1R7-S9, 17.3R3-S12, 17.4R3-S5, 18.1R3-S13, and many more up to version 21.1R2 on MX Series platforms.
Exploitation Mechanism
As of the latest information, there have been no reported cases of malicious exploitation of this vulnerability by Juniper SIRT.
Mitigation and Prevention
To address CVE-2021-31366 and prevent potential exploits, consider the following mitigation strategies.
Immediate Steps to Take
Always configure a domain map 'none' to help safeguard against this vulnerability.
Long-Term Security Practices
Continuously monitor for software updates and security advisories from Juniper Networks to stay protected against emerging threats.
Patching and Updates
Ensure that you update your Junos OS to the patched versions provided by Juniper Networks, including 15.1R7-S9, 17.3R3-S12, and subsequent releases.