CVE-2015-8345
Description
An infinite-loop flaw was discovered in the QEMU emulator built with i8255x (PRO100) emulation support. When processing a chain of commands located in the Command Block List(CBL), each Command Block(CB) points to the next command in the list. If the link to the next CB pointed to the same block or if there was a closed loop in the chain, an infinite loop would execute the same command over and over again. A privileged user inside the guest could use this flaw to crash the QEMU instance, resulting in denial of service.
Statement
This issue affects the kvm package as shipped with Red Hat Enterprise Linux 5.
This issue affects the versions of the qemu-kvm packages as shipped with Red Hat Enterprise Linux 6 and 7.
This issue affects the Red Hat Enterprise Linux 6 based versions of qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3.
This issue affects the Red Hat Enterprise Linux 7 based versions of the qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3.
This has been rated as having Moderate security impact and 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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.2 | 2.1 | 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 | Partial | 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:P
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 Qinghao Tang (QIHU 360 Marvel Team) for reporting this issue.
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