Thursday, 4 January 2018

Meltdown, Spectre: The password theft bugs at the heart of Intel CPUs. AMD, Arm also affected by data-leak design blunders


The severe design flaw in Intel microprocessors that allows sensitive data, such as passwords and crypto-keys, to be stolen from memory is real – and its details have been revealed.

A blueprint blunder in Intel's CPUs could allow applications, malware, and JavaScript running in web browsers, to obtain information they should not be allowed to access: the contents of the operating system kernel's private memory areas. These zones often contain files cached from disk, a view onto the machine's entire physical memory, and other secrets. This should be invisible to normal programs.

Thanks to Intel's cockup – now codenamed Meltdown – that data is potentially accessible, meaning bad websites and malware can attempt to rifle through the computer's memory looking for credentials, RNG seeds, personal information, and more.

Intel is not just affected. Arm and AMD processors are as well – to varying degrees. AMD insisted there is a "near-zero" risk its chips can be attacked in some scenarios, but its CPUs are vulnerable in others. The chip designer has put up a basic page that attempts to play down the impact of the bugs on its hardware.

This is, essentially, a mega-gaffe by the semiconductor industry. As they souped up their CPUs to race them against each other, they left behind one thing in the dust. Security.

Programmers are scrambling to overhaul the open-source Linux kernel's virtual memory system. Meanwhile, Microsoft is expected to publicly introduce the necessary changes to its Windows operating system in an upcoming Patch Tuesday: these changes were seeded to beta testers running fast-ring Windows Insider builds in November and December.

Crucially, these updates to both Linux and Windows will incur a performance hit on Intel products. The effects are still being benchmarked, however we're looking at a ballpark figure of five to 30 per cent slow down, depending on the task and the processor model.

Similar operating systems, such as Apple's 64-bit macOS, will also need to be updated – the flaw is in the Intel x86-64 hardware, and it appears a microcode update can't address it. It has to be fixed in software at the OS level, or go buy a new processor without the design blunder.


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