CVE-2019-3901 Explained : Impact and Mitigation
Learn about CVE-2019-3901, a vulnerability in the Linux kernel before version 4.8 allowing local attackers to access sensitive data from setuid programs. Understand the impact, affected systems, exploitation mechanism, and mitigation steps.
CVE-2019-3901 is a vulnerability in the Linux kernel before version 4.8 that allows local attackers to access sensitive data from setuid programs. This is due to a race condition in perf_event_open() where proper locks are not held during the ptrace_may_access() call.
Understanding CVE-2019-3901
This CVE affects the Linux kernel versions older than 4.8.
What is CVE-2019-3901?
Before kernel version 4.8, a race condition in perf_event_open() allows local attackers to access sensitive data from setuid programs by bypassing security checks.
The Impact of CVE-2019-3901
- Base Score: 5.6 (Medium)
- Attack Vector: Local
- Attack Complexity: High
- Privileges Required: Low
- Confidentiality Impact: High
- Integrity Impact: None
- Scope: Changed
- User Interaction: None
- Availability Impact: None
- CVE Type: CWE-667
Technical Details of CVE-2019-3901
This section provides more in-depth technical information about the vulnerability.
Vulnerability Description
The race condition in perf_event_open() allows attackers to access sensitive data from setuid programs by exploiting a lack of proper locks during the ptrace_may_access() call.
Affected Systems and Versions
- Affected Product: Kernel
- Vendor: The Linux Foundation
- Affected Versions: Older than 4.8
Exploitation Mechanism
Attackers can exploit this vulnerability by executing an execve() syscall with setuid privileges before perf_event_alloc() attaches to the target task, bypassing security checks.
Mitigation and Prevention
Protecting systems from CVE-2019-3901 involves taking immediate steps and implementing long-term security practices.
Immediate Steps to Take
- Update the Linux kernel to version 4.8 or newer.
- Monitor and restrict access to sensitive data.
Long-Term Security Practices
- Regularly update and patch the kernel and other software components.
- Implement least privilege access controls to limit potential attack surfaces.
- Conduct regular security audits and penetration testing.
Patching and Updates
- Apply security updates provided by Linux distributions and vendors.