CVE-2019-15718 : Security Advisory and Response
Learn about CVE-2019-15718, a vulnerability in systemd 240 that enables unauthorized users to change DNS resolver settings by exploiting restricted D-Bus methods. Find mitigation steps and long-term security practices here.
In the systemd version 240, a vulnerability exists that allows unauthorized users to manipulate the system's DNS resolver settings by exploiting D-Bus methods typically restricted to privileged users.
Understanding CVE-2019-15718
What is CVE-2019-15718?
In systemd 240, a function in the shared/bus-util.c file disables access controls for incoming D-Bus messages, enabling unauthorized users to change DNS resolver settings.
The Impact of CVE-2019-15718
This vulnerability permits unprivileged users to alter the system's DNS resolver settings by executing restricted D-Bus methods.
Technical Details of CVE-2019-15718
Vulnerability Description
The vulnerability in systemd 240 allows unauthorized users to manipulate DNS resolver settings by exploiting D-Bus methods restricted to privileged users.
Affected Systems and Versions
- Product: N/A
- Vendor: N/A
- Version: N/A
Exploitation Mechanism
Unauthorized users can exploit the vulnerability by executing D-Bus methods that should be restricted to privileged users, thereby changing the system's DNS resolver settings.
Mitigation and Prevention
Immediate Steps to Take
- Update systemd to a patched version that addresses the vulnerability.
- Monitor system logs for any unusual DNS resolver setting changes.
Long-Term Security Practices
- Implement least privilege access controls to restrict unauthorized access.
- Regularly review and update access control policies to prevent similar vulnerabilities.
Patching and Updates
Apply patches provided by the system vendor to mitigate the vulnerability.