CVE-2015-5307
Description
It was found that the x86 ISA (Instruction Set Architecture) is prone to a denial of service attack inside a virtualized environment in the form of an infinite loop in the microcode due to the way (sequential) delivering of benign exceptions such as #AC (alignment check exception) is handled. A privileged user inside a guest could use this flaw to create denial of service conditions on the host kernel.
Statement
This issue affects the version of the kvm and xen packages as shipped with Red Hat Enterprise Linux 5.
This issue does not affect the versions of the kernel package as shipped with Red Hat Enterprise Linux 5 and Red Hat Enterprise MRG 2.
This issue affects the version of Linux kernel as shipped with Red Hat Enterprise Linux 6 and 7. Future kernel updates for the respective releases may address this issue.
Red Hat Enterprise Linux 5 is now in Production Phase 3 of the support and maintenance life cycle. Thus it is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
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).
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.2 | 4.9 | N/A |
| Attack Vector | Adjacent Network | Local | N/A |
| Access Complexity | Medium | Low | N/A |
| Authentication | Single | None | N/A |
| Confidentiality Impact | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Complete | Complete | N/A |
Vector
Red Hat: AV:A/AC:M/Au:S/C:N/I:N/A:C
NVD: AV:L/AC:L/Au:N/C:N/I:N/A:C
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Amplification
An infinite loop will cause unexpected consumption of resources, such as CPU cycles or memory. The software's operation may slow down, or cause a long time to respond.
Acknowledgements
Red Hat would like to thank Ben Serebrin (Google Inc.) for reporting this issue.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
