CVE-2021-27391 Explained : Impact and Mitigation
Learn about CVE-2021-27391, a severe buffer overflow vulnerability impacting Siemens products. Unauthenticated attackers could execute arbitrary code with root privileges.
A vulnerability has been identified in various Siemens products including APOGEE MBC, APOGEE MEC, APOGEE PXC Compact, APOGEE PXC Modular, and TALON TC Compact and Modular series. The vulnerability arises from the lack of proper bounds checking on the web server when parsing HTTP requests, potentially leading to a buffer overflow vulnerability. An attacker could exploit this flaw to execute arbitrary code with root privileges.
Understanding CVE-2021-27391
This section provides insights into the specifics of the CVE-2021-27391 vulnerability.
What is CVE-2021-27391?
CVE-2021-27391 is a buffer overflow vulnerability found in a range of Siemens products due to inadequate input validation on the web server, allowing attackers to execute arbitrary code remotely.
The Impact of CVE-2021-27391
The impact of this vulnerability is severe as an unauthenticated remote attacker could exploit it to gain root privileges on the affected device.
Technical Details of CVE-2021-27391
In this section, we delve into the technical aspects of the CVE-2021-27391 vulnerability.
Vulnerability Description
The vulnerability stems from the lack of proper input validation in the web server of affected Siemens devices, potentially leading to a buffer overflow.
Affected Systems and Versions
Products affected include APOGEE MBC (PPC), APOGEE MEC (PPC), APOGEE PXC Compact (BACnet), APOGEE PXC Modular, TALON TC Compact, and TALON TC Modular series.
Exploitation Mechanism
Attackers can exploit this vulnerability by sending specially crafted HTTP requests with malicious Host parameters to trigger a buffer overflow.
Mitigation and Prevention
This section outlines the steps to mitigate and prevent exploitation of CVE-2021-27391.
Immediate Steps to Take
Users are advised to apply security patches provided by Siemens to address the vulnerability as soon as possible. Additionally, implementing network security measures to restrict access to affected devices is recommended.
Long-Term Security Practices
To enhance the security posture of the affected devices, regular security assessments, network segmentation, and security training for personnel are advisable.
Patching and Updates
Regularly check Siemens' official security advisories and apply relevant patches and updates to safeguard against potential security risks.