Describe CVE-2015-2877.
What is CVE-2015-2877?
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.