CVE-2020-12826 Explained : Impact and Mitigation
Learn about CVE-2020-12826, a signal access-control issue in the Linux kernel before 5.6.5, allowing unauthorized signal transmission between processes. Find mitigation steps and patching details.
A signal access-control issue was discovered in the Linux kernel before 5.6.5, aka CID-7395ea4e65c2. An integer overflow in exec_id can allow a child process to send signals to a parent process in a different security domain.
Understanding CVE-2020-12826
This CVE involves a vulnerability in the Linux kernel that could potentially lead to unauthorized signal access between processes.
What is CVE-2020-12826?
The issue arises from a 32-bit limitation in the exec_id field in include/linux/sched.h, enabling an integer overflow that can bypass the do_notify_parent protection mechanism.
The Impact of CVE-2020-12826
The vulnerability allows a child process to send arbitrary signals to a parent process in a separate security domain, potentially compromising system integrity and security.
Technical Details of CVE-2020-12826
This section delves into the specific technical aspects of the CVE.
Vulnerability Description
The flaw in the Linux kernel before version 5.6.5 permits an integer overflow due to the limited size of the exec_id field, enabling unauthorized signal transmission between processes.
Affected Systems and Versions
- Affected: Linux kernel versions before 5.6.5
- Not affected: Specific product or vendor mentioned
Exploitation Mechanism
- Exploitation relies on triggering an integer overflow in the exec_id field
- Child processes can exploit this to send signals to parent processes in different security domains
Mitigation and Prevention
Protecting systems from CVE-2020-12826 requires immediate actions and long-term security practices.
Immediate Steps to Take
- Apply relevant security patches and updates promptly
- Monitor system logs for any suspicious activity related to signal handling
Long-Term Security Practices
- Implement least privilege principles to restrict process capabilities
- Regularly review and update security configurations to mitigate similar vulnerabilities
Patching and Updates
- Update to Linux kernel version 5.6.5 or newer to address the signal access-control issue