CVE-2021-27363 : Security Advisory and Response

An issue was discovered in the Linux kernel through 5.11.3 related to a kernel pointer leak in the iscsi_transport structure.

Understanding CVE-2021-27363

This CVE highlights a vulnerability in the Linux kernel that allows unprivileged users to access a pointer to an iscsi_transport struct, posing a security risk.

What is CVE-2021-27363?

The CVE-2021-27363 vulnerability in the Linux kernel through version 5.11.3 exposes the handle address of an iSCSI transport, potentially compromising system integrity.

The Impact of CVE-2021-27363

This vulnerability enables unauthorized users to access sensitive kernel data, leading to potential exploitation and security breaches within affected systems.

Technical Details of CVE-2021-27363

The vulnerability stems from a kernel pointer leak within the iscsi_transport structure, allowing unauthorized access to critical system information.

Vulnerability Description

When an iSCSI transport is registered with the iSCSI subsystem, unprivileged users can obtain the transport's handle through the sysfs file system, exposing sensitive kernel data.

Affected Systems and Versions

Linux kernel versions up to 5.11.3 are affected by this vulnerability, potentially impacting a wide range of systems still running outdated kernel versions.

Exploitation Mechanism

By reading the show_transport_handle function in drivers/scsi/scsi_transport_iscsi.c, the pointer to an iscsi_transport struct is leaked, providing unauthorized access to critical system data.

Mitigation and Prevention

Addressing CVE-2021-27363 requires immediate actions to prevent potential security threats and ensure system integrity.

Immediate Steps to Take

Update to a patched version of the Linux kernel, implement access controls, and monitor system activity for any unauthorized access attempts.

Long-Term Security Practices

Regularly update the Linux kernel to the latest secure versions, conduct security audits, and enforce least privilege access to mitigate similar vulnerabilities.

Patching and Updates

Stay informed about security advisories, apply security patches promptly, and ensure best practices in system hardening and security configuration.