CVE-2021-3739 : Exploit Details and Defense Strategies
Learn about CVE-2021-3739, a NULL pointer dereference flaw in the Linux Kernel that could allow local attackers to crash the system or leak sensitive information. Find out about the impact, affected systems, and mitigation steps.
A NULL pointer dereference vulnerability was discovered in the btrfs_rm_device function in the Linux Kernel, specifically in fs/btrfs/volumes.c. This vulnerability, identified as CVE-2021-3739, requires 'CAP_SYS_ADMIN' privileges to be triggered. Exploiting this flaw could allow a local attacker to crash the system or potentially reveal sensitive kernel information, posing a significant risk to system availability.
Understanding CVE-2021-3739
This section delves into the details of the CVE-2021-3739 vulnerability.
What is CVE-2021-3739?
The CVE-2021-3739 vulnerability is classified under CWE-476, which pertains to a NULL Pointer Dereference flaw. It can be exploited by an attacker with specific privileges to cause a system crash or disclose kernel internals.
The Impact of CVE-2021-3739
The highest risk associated with CVE-2021-3739 is the potential compromise of system availability, as a local attacker could exploit the vulnerability to disrupt system operations and potentially glean sensitive information.
Technical Details of CVE-2021-3739
This section provides a deeper insight into the technical aspects of CVE-2021-3739.
Vulnerability Description
The vulnerability arises from a NULL pointer dereference in the btrfs_rm_device function within the Linux Kernel, present in fs/btrfs/volumes.c.
Affected Systems and Versions
The vulnerability affects the Linux Kernel and is specifically fixed in version v5.15-rc1 and above.
Exploitation Mechanism
To trigger the CVE-2021-3739 vulnerability, an attacker must possess 'CAP_SYS_ADMIN' privileges, enabling them to potentially crash the system or extract sensitive kernel data.
Mitigation and Prevention
This section outlines the necessary steps to mitigate the risks associated with CVE-2021-3739.
Immediate Steps to Take
System administrators are advised to apply relevant patches and updates promptly to address the CVE-2021-3739 vulnerability.
Long-Term Security Practices
Implementing robust privilege management and access control measures can help prevent unauthorized exploitation of vulnerabilities like CVE-2021-3739.
Patching and Updates
Regularly updating the Linux Kernel to versions v5.15-rc1 and beyond is crucial to safeguard systems against the CVE-2021-3739 vulnerability.