** DISPUTED ** Kernel Samepage Merging (KSM) in the Linux kernel 2.6.32 through 4.x does not prevent use of a write-timing side channel, which allows guest OS users to defeat the ASLR protection mechanism on other guest OS instances via a Cross-VM ASL INtrospection (CAIN) attack. NOTE: the vendor states "Basically if you care about this attack vector, disable deduplication." Share-until-written approaches for memory conservation among mutually untrusting tenants are inherently detectable for information disclosure, and can be classified as potentially misunderstood behaviors rather than vulnerabilities.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2015-2877 from the MITRE CVE dictionary dictionary and NIST NVD.
This issue affects the versions of the Linux Kernel as shipped with Red Hat Enterprise Linux 4, 5, 6 and 7. Red Hat Product Security has rated this issue as having Low security impact. Additionally a workaround is available. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.
| Base Score | 2.1 |
|---|---|
| Base Metrics | AV:L/AC:L/Au:N/C:P/I:N/A:N |
| Access Vector | Local |
| Access Complexity | Low |
| Authentication | None |
| Confidentiality Impact | Partial |
| Integrity Impact | None |
| Availability Impact | None |
Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 7 | kernel | Will not fix |
| Red Hat Enterprise Linux 6 | kernel | Will not fix |
| Red Hat Enterprise Linux 5 | kernel | Will not fix |
| Red Hat Enterprise Linux 4 | kernel | Will not fix |
Vulmon