CVE-2015-2877
Description
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
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2015-2877
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| debian | bookworm | affected | |
| debian | bullseye | affected | |
| debian | forky | affected | |
| debian | sid | affected | |
| debian | trixie | affected | |
| linux-kernel | affected | | |
| rhel | 4.0 | affected | |
| rhel | 5.0 | affected | |
| rhel | 6.0 | affected | |
| rhel | 7.0 | affected | |
References
- http://www.antoniobarresi.com/files/cain_advisory.txt
- http://www.kb.cert.org/vuls/id/935424
- http://www.securityfocus.com/bid/76256
- https://bugzilla.redhat.com/show_bug.cgi?id=1252096
- https://www.kb.cert.org/vuls/id/BGAR-A2CNKG
- https://www.kb.cert.org/vuls/id/BLUU-9ZAHZH
- https://www.usenix.org/system/files/conference/woot15/woot15-paper-barresi.pdf
- https://security-tracker.debian.org/tracker/CVE-2015-2877
CWEs
CWE-200
Verify integrity in audit chain (admin only). AS-IS.