CVE-2017-15649 : Exploit Details and Defense Strategies

In versions of the Linux kernel prior to 4.13.6, a vulnerability exists in the net/packet/af_packet.c file that allows local users to gain elevated privileges by exploiting certain system calls. This vulnerability results from a race condition between fanout_add and packet_do_bind functions, leading to a use-after-free scenario.

Understanding CVE-2017-15649

This CVE entry highlights a security flaw in the Linux kernel that could be leveraged by local users to escalate their privileges.

What is CVE-2017-15649?

The vulnerability in the net/packet/af_packet.c file of Linux kernels before version 4.13.6 enables local users to elevate their privileges through specific malicious system calls that trigger mishandling of packet_fanout data structures due to a race condition.

The Impact of CVE-2017-15649

The exploitation of this vulnerability could allow unauthorized users to gain elevated privileges on the affected system, potentially leading to unauthorized access and control.

Technical Details of CVE-2017-15649

This section delves into the technical aspects of the CVE, including the vulnerability description, affected systems, and the exploitation mechanism.

Vulnerability Description

The vulnerability arises from a race condition involving the fanout_add and packet_do_bind functions in the net/packet/af_packet.c file, resulting in a use-after-free scenario that can be exploited by local users to escalate privileges.

Affected Systems and Versions

Affected Systems: Linux kernels before version 4.13.6
Affected Versions: Not applicable

Exploitation Mechanism

Local users can exploit the vulnerability by making specific system calls that trigger mishandling of packet_fanout data structures.
The race condition between fanout_add and packet_do_bind functions leads to a use-after-free scenario, enabling privilege escalation.

Mitigation and Prevention

Protecting systems from CVE-2017-15649 requires immediate steps and long-term security practices.

Immediate Steps to Take

Update the Linux kernel to version 4.13.6 or newer to mitigate the vulnerability.
Monitor system logs for any suspicious activities that could indicate exploitation attempts.

Long-Term Security Practices

Implement the principle of least privilege to restrict user access and minimize the impact of potential security breaches.
Regularly apply security patches and updates to ensure the system is protected against known vulnerabilities.
Conduct security training for users to raise awareness about best practices and potential security risks.

Patching and Updates

Stay informed about security advisories and updates from Linux distributions and vendors to promptly apply patches for known vulnerabilities.