CVE-2021-27393 : Security Advisory and Response
Discover the impact of CVE-2021-27393 on Siemens Nucleus NET, ReadyStart V3, and Source Code. Learn about the vulnerability, affected versions, exploitation risks, and mitigation strategies.
A vulnerability has been identified in Nucleus NET, Nucleus ReadyStart V3, and Nucleus Source Code by Siemens. The issue lies in the DNS client's improper randomization of UDP port numbers for DNS requests, potentially enabling DNS cache poisoning or DNS resolution spoofing.
Understanding CVE-2021-27393
This CVE pertains to a vulnerability in Siemens' Nucleus NET, Nucleus ReadyStart V3, and Nucleus Source Code versions.
What is CVE-2021-27393?
CVE-2021-27393 points to a flaw in the DNS client functionality across affected Siemens products, undermining the randomization of UDP port numbers in DNS requests.
The Impact of CVE-2021-27393
The vulnerability could be exploited by threat actors to manipulate DNS responses, leading to DNS cache poisoning, or to deceive systems into false DNS resolutions.
Technical Details of CVE-2021-27393
The vulnerability involves the mishandling of UDP port randomization in DNS requests, affecting the integrity of DNS processes.
Vulnerability Description
The issue arises from the DNS client's failure to adequately randomize UDP port numbers, paving the way for potential DNS cache attacks.
Affected Systems and Versions
All versions of Nucleus NET, Nucleus ReadyStart V3 older than V2013.08, and Nucleus Source Code with impacted DNS modules are vulnerable.
Exploitation Mechanism
Exploiting this vulnerability could allow attackers to poison DNS caches or falsify DNS resolutions, creating security risks.
Mitigation and Prevention
To address CVE-2021-27393, immediate actions and long-term security measures are crucial.
Immediate Steps to Take
Users should apply patches and updates provided by Siemens promptly to safeguard their systems against potential DNS attacks.
Long-Term Security Practices
Implementing robust network security protocols and monitoring DNS traffic for anomalies can enhance overall cybersecurity posture.
Patching and Updates
Regularly update affected Siemens products, including Nucleus NET, Nucleus ReadyStart V3, and Nucleus Source Code, to mitigate the risk of DNS-related exploits.