CVE-2013-1943
Description
From CVE.org
The KVM subsystem in the Linux kernel before 3.0 does not check whether kernel addresses are specified during allocation of memory slots for use in a guest's physical address space, which allows local users to gain privileges or obtain sensitive information from kernel memory via a crafted application, related to arch/x86/kvm/paging_tmpl.h and virt/kvm/kvm_main.c.
Statement
This issue does not affect the versions of Linux kernel as shipped with Red Hat Enterprise MRG 2.
Future kvm updates for Red Hat Enterprise Linux 5 may address this flaw.
This issue was addresses in Red Hat Enterprise Linux 6 via RHSA-2013:0911 (https://rhn.redhat.com/errata/RHSA-2013-0911.html).
Please note that unlike Red Hat Enterprise Linux 6, where a local unprivileged user could use this flaw to escalate their privileges on the system, on Red Hat Enterprise Linux 5, Red Hat Enterprise Linux 6.2 EUS, and Red Hat Enterprise Linux 6.3 EUS the impact is limited to potential information leak only.
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 | 6.9 | 4.4 | N/A |
| Attack Vector | Local | Local | N/A |
| Access Complexity | Medium | Medium | N/A |
| Authentication | None | None | N/A |
| Confidentiality Impact | Complete | Partial | N/A |
| Integrity Impact | Complete | Partial | N/A |
| Availability Impact | Complete | Partial | N/A |
Vector
Red Hat: AV:L/AC:M/Au:N/C:C/I:C/A:C
NVD: AV:L/AC:M/Au:N/C:P/I:P/A:P
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
This issue was discovered by Michael S. Tsirkin (Red Hat).
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
