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Meltdown & Spectre resources

The Meltdown & Spectre vulnerabilities are very much all over the technical media – but are yet to make the real news. The impacts are threefold:

Spectre Variant 1: bounds check bypass (CVE-2017-5753)

Spectre Variant 2: branch target injection (CVE-2017-5715)

Meltdown Variant 3: rogue data cache load (CVE-2017-5754)

The vulnerability was discovered by Google’s Project Zero, a new class of side channel attack. This article was posted on the Wednesday 3rd January 2018 – however, the discovery went out to chip manufacturers and vendors under non-disclosure agreement Tuesday 9th November2017. Their post followed a leak ahead of the two month embargo period ending on the Tuesday 9th January 2018. This is common procedure with such discoveries, allowing fixes to be in circulation and in place before it becomes common knowledge. However the early disclosure meant that this left a number of vendors without a workeable fix.

At this time the following links appear to be the place for updates for your specific platform (please not some of these pages may change from timelines to means to fix depending on the transparency and media choices of the provider):

Microsoft Windows

Debian

Ubuntu

CentOS

RedHat

CloudLinux

OnApp

Dell

Xen

Virtuozzo

So to recap we are looking at three issues. Spectre effecting pretty much all modern CPU’s – Intel, AMD, ARM, possibly others. Meltdown effecting Intel based CPU’s:

Spectre Variant 1 CVE-2017-5753 triggers the speculative execution by performing a bounds-check bypass. It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory accesses may cause allocation into the microprocessor’s data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to cross the syscall boundary and read privileged memory by conducting targeted cache side-channel attacks. (CVE-2017-5753, Important)

Spectre Variant 2 CVE-2017-5715 triggers the speculative execution by utilizing branch target injection. It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory accesses may cause allocation into the microprocessor’s data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to cross the syscall and guest/host boundaries and read privileged memory by conducting targeted cache side-channel attacks. (CVE-2017-5715, Important)

Meltdown Variant 3 CVE-2017-5754 relies on the fact that, on impacted microprocessors, during speculative execution of instruction permission faults, exception generation triggered by a faulting access is suppressed until the retirement of the whole instruction block. In a combination with the fact that memory accesses may populate the cache even when the block is being dropped and never committed (executed), an unprivileged local attacker could use this flaw to read privileged (kernel space) memory by conducting targeted cache side-channel attacks. (CVE-2017-5754, Important)

Note: CVE-2017-5754 affects Intel x86-64 microprocessors. AMD x86-64 microprocessors are not affected by this issue.

Our engineers will be working very closely with the vendors and their guidelines to keep our platforms as secure and stable as possible. It is likely an announcement for shared platform reboots will follow once we know more about the suggested fixes.

Regretfully, at this time our engineers will be relying on the vendors, and similar documents for information. We will update you as the situation unfolds.

 

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