CVE-2015-3214
Description
An out-of-bounds memory access flaw, leading to memory corruption or possibly an information leak, was found in QEMU's pit_ioport_read() function. A privileged guest user in a QEMU guest, which had QEMU PIT emulation enabled, could potentially, in rare cases, use this flaw to execute arbitrary code on the host with the privileges of the hosting QEMU process.
Statement
This issue does not affect the versions of the qemu and qemu-kvm packages as shipped with Red Hat Enterprise Linux 5, 6 and Red Hat Enterprise Linux 6 based versions of qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3.
This issue does affect the Red Hat Enterprise Linux 7 qemu-kvm and Red Hat Enterprise Linux 7 based versions of the qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3. Future updates for the respective releases may address this flaw.
Please note that by default QEMU/KVM guests use in-kernel (KVM) PIT emulation in which case the following applies:
This issue does not affect the Linux kernel versions as shipped with Red Hat Enterprise Linux 5, 6, 7 and Red Hat Enterprise Linux MRG 2.
This issue does affect the kvm package as shipped with Red Hat Enterprise Linux 5.
Red Hat Enterprise Linux 5 is now in Production 3 Phase of the support and maintenance life cycle. 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).
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | 6.9 | N/A |
| Attack Vector | Adjacent Network | Local | N/A |
| Access Complexity | High | Medium | N/A |
| Authentication | Single | 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:A/AC:H/Au:S/C:C/I:C/A:C
NVD: AV:L/AC:M/Au:N/C:C/I:C/A:C
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands; Modify Memory
If the memory accessible by the attacker can be effectively controlled, it may be possible to execute arbitrary code, as with a standard buffer overflow. If the attacker can overwrite a pointer's worth of memory (usually 32 or 64 bits), they can alter the intended control flow by redirecting a function pointer to their own malicious code. Even when the attacker can only modify a single byte arbitrary code execution can be possible. Sometimes this is because the same problem can be exploited repeatedly to the same effect. Other times it is because the attacker can overwrite security-critical application-specific data -- such as a flag indicating whether the user is an administrator.
Availability,Confidentiality
Technical Impact: Read Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
Out of bounds memory access will very likely result in the corruption of relevant memory, and perhaps instructions, possibly leading to a crash. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.
Confidentiality
Technical Impact: Read Memory
In the case of an out-of-bounds read, the attacker may have access to sensitive information. If the sensitive information contains system details, such as the current buffer's position in memory, this knowledge can be used to craft further attacks, possibly with more severe consequences.
Acknowledgements
Red Hat would like to thank Matt Tait (Google's Project Zero security team) for reporting this issue.
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