CVE-2021-3923 : Security Advisory and Response
Learn about CVE-2021-3923, a flaw in Linux kernel's RDMA over Infiniband implementation allowing attackers to leak kernel stack information and potentially bypass security mechanisms.
A flaw was discovered in the Linux kernel's implementation of RDMA over Infiniband, allowing a privileged local attacker to leak kernel stack information. Although the leaked data may not expose sensitive user information directly, it can potentially bypass existing kernel protection mechanisms.
Understanding CVE-2021-3923
This section delves deeper into the impact and technical details of CVE-2021-3923.
What is CVE-2021-3923?
CVE-2021-3923 involves a vulnerability in the Linux kernel's handling of RDMA over Infiniband, enabling a local attacker to disclose kernel stack data via specific commands.
The Impact of CVE-2021-3923
While the vulnerability may not pose an immediate risk to user data, it can be leveraged to circumvent kernel security measures and potentially facilitate further attacks.
Technical Details of CVE-2021-3923
In this section, we explore the specifics of the vulnerability, affected systems, and exploitation mechanism.
Vulnerability Description
The flaw in the RDMA over Infiniband implementation allows a privileged local account to extract kernel stack information by interacting with a specific device node.
Affected Systems and Versions
The vulnerability impacts the Linux kernel with specifics around RDMA over Infiniband, but exact affected versions are currently reported as unknown.
Exploitation Mechanism
An attacker with privileged local access can exploit this vulnerability by issuing certain commands to the /dev/infiniband/rdma_cm device node.
Mitigation and Prevention
This section outlines immediate steps that can be taken to address CVE-2021-3923 and enhance long-term security measures.
Immediate Steps to Take
Ensure monitoring of privileged account activities, restrict access to critical nodes, and deploy intrusion detection systems to detect any attempts at exploiting the vulnerability.
Long-Term Security Practices
Implement a least privilege access policy, keep systems and software updated regularly, conduct security assessments, and provide training on secure coding practices.
Patching and Updates
Stay informed about patches released by the Linux kernel maintainers and promptly apply relevant security updates to mitigate the risk associated with CVE-2021-3923.