CVE-2015-8556
Description
A Time of Creation To Time of Usage (TOCTTOU) flaw was discovered in the QEMU emulator built with VirtFS(file system pass-through) support to share folders between host and guest. The flaw occurs if the 'virtfs-proxy-helper' program is installed with SUID permissions or has 'CAP_CHOWN' capability. An unprivileged, local attacker could exploit this flaw to potentially escalate their privileges and gain root access to the system.
Statement
This issue does not affect the versions of the kvm and xen packages as shipped with Red Hat Enterprise Linux 5.
This issue does not affect the versions of the qemu-kvm packages as shipped with Red Hat Enterprise Linux 6, and the Red Hat Enterprise Linux 6 based versions of qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3.
This issue does not affect the versions of the qemu-kvm packages as shipped with Red Hat Enterprise Linux 7.
This issue does not affect the Red Hat Enterprise Linux 7 based versions of the qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3.
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 | 6.2 | 10 | N/A |
| Attack Vector | Local | Network | N/A |
| Access Complexity | High | Low | N/A |
| Authentication | None | None | N/A |
| Confidentiality Impact | Complete | Complete | N/A |
| Integrity Impact | Complete | Complete | N/A |
| Availability Impact | Complete | Complete | N/A |
Vector
Red Hat: AV:L/AC:H/Au:N/C:C/I:C/A:C
NVD: AV:N/AC:L/Au:N/C:C/I:C/A:C
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability,Access Control
Technical Impact: Gain Privileges or Assume Identity; Execute Unauthorized Code or Commands; Read Application Data; DoS: Crash, Exit, or Restart
An attacker will be able to gain access to any resources that are allowed by the extra privileges. Common results include executing code, disabling services, and reading restricted data. New weaknesses can be exposed because running with extra privileges, such as root or Administrator, can disable the normal security checks being performed by the operating system or surrounding environment. Other pre-existing weaknesses can turn into security vulnerabilities if they occur while operating at raised privileges.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
