CVE-2015-2877
Publication date 3 March 2017
Last updated 24 July 2024
Ubuntu priority
Cvss 3 Severity Score
** 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.
Mitigation
If qemu-kvm is installed, set KSM_ENABLED=0 in /etc/default/qemu-kvm, otherwise will need to echo -n 0 > /sys/kernel/mm/ksm/run
Status
Package | Ubuntu Release | Status |
---|---|---|
linux | ||
18.04 LTS bionic | Ignored architectural limitation of KSM | |
16.04 LTS xenial | Ignored architectural limitation of KSM | |
14.04 LTS trusty | Ignored architectural limitation of KSM | |
linux-armadaxp | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-aws | ||
18.04 LTS bionic | Ignored architectural limitation of KSM | |
16.04 LTS xenial | Ignored architectural limitation of KSM | |
14.04 LTS trusty | Ignored architectural limitation of KSM | |
linux-azure | ||
18.04 LTS bionic | Ignored architectural limitation of KSM | |
16.04 LTS xenial | Ignored architectural limitation of KSM | |
14.04 LTS trusty | Ignored architectural limitation of KSM | |
linux-azure-edge | ||
18.04 LTS bionic | Ignored architectural limitation of KSM | |
16.04 LTS xenial | Ignored end of standard support | |
14.04 LTS trusty | Not in release | |
linux-ec2 | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-euclid | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Ignored architectural limitation of KSM | |
14.04 LTS trusty | Not in release | |
linux-flo | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Ignored abandoned | |
14.04 LTS trusty | Not in release | |
linux-fsl-imx51 | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-gcp | ||
18.04 LTS bionic | Ignored architectural limitation of KSM | |
16.04 LTS xenial | Ignored architectural limitation of KSM | |
14.04 LTS trusty | Not in release | |
linux-gke | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Ignored end of life, was needed | |
14.04 LTS trusty | Not in release | |
linux-goldfish | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Ignored abandoned | |
14.04 LTS trusty | Not in release | |
linux-grouper | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-hwe | ||
18.04 LTS bionic | Ignored architectural limitation of KSM | |
16.04 LTS xenial | Ignored architectural limitation of KSM | |
14.04 LTS trusty | Not in release | |
linux-hwe-edge | ||
18.04 LTS bionic | Ignored architectural limitation of KSM | |
16.04 LTS xenial | Ignored architectural limitation of KSM | |
14.04 LTS trusty | Not in release | |
linux-kvm | ||
18.04 LTS bionic | Ignored architectural limitation of KSM | |
16.04 LTS xenial | Ignored architectural limitation of KSM | |
14.04 LTS trusty | Not in release | |
linux-linaro-omap | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-linaro-shared | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-linaro-vexpress | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-lts-quantal | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-lts-raring | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-lts-saucy | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-lts-trusty | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-lts-utopic | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Ignored end of life, was ignored | |
linux-lts-vivid | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Ignored end of life, was ignored | |
linux-lts-wily | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Ignored end of life, was ignored | |
linux-lts-xenial | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Ignored architectural limitation of KSM | |
linux-maguro | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-mako | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Ignored abandoned | |
14.04 LTS trusty | Not in release | |
linux-manta | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-mvl-dove | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-oem | ||
18.04 LTS bionic | Ignored architectural limitation of KSM | |
16.04 LTS xenial | Ignored end of life | |
14.04 LTS trusty | Not in release | |
linux-qcm-msm | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
linux-raspi2 | ||
18.04 LTS bionic | Ignored end of standard support | |
16.04 LTS xenial | Ignored architectural limitation of KSM | |
14.04 LTS trusty | Not in release | |
linux-snapdragon | ||
18.04 LTS bionic | Ignored end of standard support | |
16.04 LTS xenial | Ignored architectural limitation of KSM | |
14.04 LTS trusty | Not in release | |
linux-ti-omap4 | ||
18.04 LTS bionic | Not in release | |
16.04 LTS xenial | Not in release | |
14.04 LTS trusty | Not in release | |
Notes
tyhicks
The behavior represented by CVE-2015-2877 is inherent to Kernel Samepage Merging. To mitigate the issue, follow the steps above to disable KSM.
Severity score breakdown
Parameter | Value |
---|---|
Base score | 3.3 · Low |
Attack vector | Local |
Attack complexity | Low |
Privileges required | Low |
User interaction | None |
Scope | Unchanged |
Confidentiality | Low |
Integrity impact | None |
Availability impact | None |
Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |