CVE-2020-15863
Description
A buffer overflow vulnerability was found in the XGMAC Ethernet controller of the QEMU emulator. This flaw occurs during packet transmission and affects the highbank and midway emulated machines. A guest user or process could use this flaw to crash the QEMU process on the host, resulting in a denial of service or potential code execution with the privileges of the QEMU process.
Statement
The XGMAC device can only be found on highbank and midway QEMU ARM emulated machines. This flaw did not affect the following versions of QEMU as they did not include support for XGMAC:
qemu-kvm-maas shipped with Red Hat Enterprise Linux 7.qemu-kvm-rhevas shipped with Red Hat Virtualization and Red Hat OpenStack.qemu-kvmas shipped with Red Hat Enterprise Linux 6, 7 and 8.virt:8.2/qemu-kvmas shipped with RHEL Advanced Virtualization.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | 5.3 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Changed | Changed | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | Low | Low | N/A |
| Availability Impact | Low | Low | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L
NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L
Understanding the Weakness (CWE)
Availability
Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.
Integrity,Confidentiality,Availability,Access Control
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands; Bypass Protection Mechanism
Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy.
Integrity,Confidentiality,Availability,Access Control,Other
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Other
When the consequence is arbitrary code execution, this can often be used to subvert any other security service.
Acknowledgements
Red Hat would like to thank Ziming Zhang (Codesafe Team of Legendsec at Qi'anxin Group) for reporting this issue.
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