CVE-2020-15564 : Exploit Details and Defense Strategies
Discover how CVE-2020-15564 in Xen through 4.13.x allows Arm guest OS users to trigger a hypervisor crash due to a missing alignment check, leading to a Denial of Service (DoS) attack. Learn about affected systems, exploitation, and mitigation.
An issue was discovered in Xen through 4.13.x, allowing Arm guest OS users to cause a hypervisor crash due to a missing alignment check in VCPUOP_register_vcpu_info. This vulnerability could be exploited by a malicious guest to trigger a Denial of Service (DoS) attack.
Understanding CVE-2020-15564
This CVE identifies a vulnerability in Xen that affects Arm guest OS users, potentially leading to a hypervisor crash.
What is CVE-2020-15564?
The vulnerability in Xen through version 4.13.x allows malicious Arm guest OS users to exploit a missing alignment check in VCPUOP_register_vcpu_info, leading to a hypervisor crash. The issue arises from the lack of validation for the alignment of addresses provided by the guest.
The Impact of CVE-2020-15564
The vulnerability could be leveraged by a malicious guest to cause a hypervisor crash, resulting in a Denial of Service (DoS) condition. All Xen versions are susceptible to this issue, with only Arm systems being vulnerable.
Technical Details of CVE-2020-15564
This section provides technical insights into the vulnerability.
Vulnerability Description
The vulnerability stems from a missing alignment check in VCPUOP_register_vcpu_info, allowing malicious Arm guest OS users to crash the hypervisor.
Affected Systems and Versions
- All Xen versions up to 4.13.x are affected
- Only Arm systems are vulnerable; x86 systems are not impacted
Exploitation Mechanism
The vulnerability can be exploited by passing a misaligned address to the hypercall VCPUOP_register_vcpu_info, causing a hypervisor crash.
Mitigation and Prevention
To address CVE-2020-15564, follow these mitigation strategies:
Immediate Steps to Take
- Apply patches provided by Xen to fix the alignment check issue
- Monitor system logs for any suspicious activities
Long-Term Security Practices
- Regularly update Xen to the latest version to mitigate known vulnerabilities
- Implement strict access controls to prevent unauthorized system access
Patching and Updates
- Stay informed about security advisories from Xen and promptly apply patches to secure the system