CVE-2017-17449 : Exploit Details and Defense Strategies
Learn about CVE-2017-17449, a vulnerability in the Linux kernel allowing local users to access confidential information. Find mitigation steps and long-term security practices here.
In the Linux kernel up to version 4.14.4, a vulnerability exists in the __netlink_deliver_tap_skb function in net/netlink/af_netlink.c. This flaw allows local users with CAP_NET_ADMIN capability to access sensitive information by monitoring an nlmon interface.
Understanding CVE-2017-17449
This CVE entry highlights a security issue in the Linux kernel that could be exploited by local users to obtain confidential data.
What is CVE-2017-17449?
The vulnerability arises due to the lack of restrictions on Netlink message observations to a specific net namespace when the CONFIG_NLMON feature is enabled. This oversight enables unauthorized access to sensitive information.
The Impact of CVE-2017-17449
The vulnerability allows local users with specific capabilities to intercept Netlink messages, potentially leading to unauthorized access to confidential data on the system.
Technical Details of CVE-2017-17449
This section delves into the technical aspects of the vulnerability.
Vulnerability Description
The __netlink_deliver_tap_skb function in the Linux kernel through version 4.14.4 does not limit Netlink message observations to a single net namespace, facilitating unauthorized access to sensitive information.
Affected Systems and Versions
- Affected System: Linux kernel up to version 4.14.4
- Affected Feature: CONFIG_NLMON
Exploitation Mechanism
Local users with the CAP_NET_ADMIN capability can exploit this vulnerability by monitoring an nlmon interface to capture all Netlink activity on the system.
Mitigation and Prevention
Protecting systems from CVE-2017-17449 requires immediate actions and long-term security practices.
Immediate Steps to Take
- Disable CONFIG_NLMON if not essential
- Monitor and restrict access to nlmon interfaces
- Regularly review system logs for suspicious activities
Long-Term Security Practices
- Implement the principle of least privilege for user capabilities
- Keep the Linux kernel updated with the latest security patches
- Conduct regular security audits and penetration testing
Patching and Updates
Ensure timely installation of security patches and updates provided by Linux kernel maintainers.