What is Meltdown?
A vulnerability in some CPUs where kernel memory could be read speculatively before the permission exception took effect, with values inferred from cache traces. Mitigated by KPTI and other measures.
Field: Hardware Security
Meltdown in the explanations
Meltdown read it speculatively before that mark was checked, so KPTI removes kernel pages from the mapping altogether while user code runs.
What is the idea behind KPTI (kernel page-table isolation),…Spectre and Meltdown, disclosed in 2018, exploit the fact that although speculatively executed results are discarded, data they loaded remains in the cache; timing differences (a side channel) then reveal secrets that should be inaccessible.
Which is an example of vulnerabilities revealing attacks th…
Questions that mention Meltdown (3)
- What is the principle of the vulnerability called Meltdown, which affected some CPUs?
- What is the idea behind KPTI (kernel page-table isolation), introduced as a software countermeasure to Meltdown?
- Which is an example of vulnerabilities revealing attacks that exploit traces of speculative execution left in the cache to infer data that should not be accessible?
Related terms
Kernel page-table isolation (KPTI) System call Speculative execution Spectre Anti-rollback protection Cold boot attack Constant-time implementation Counterfeit chip eFuse Fault injection attack