Microsoft has released an update that disables Intel’s microcode Spectre mitigations.
Intel has reported issues with recently released microcode meant to address Spectre variant 2 (CVE 2017-5715 Branch Target Injection) – specifically Intel noted that this microcode can cause “higher than expected reboots and other unpredictable system behavior” and then noted that situations like this may result in “data loss or corruption”. Our own experience is that system instability can in some circumstances cause data loss or corruption. On January 22, Intel recommended that customers stop deploying the current microcode version on affected processors while they perform additional testing on the updated solution. We understand that Intel is continuing to investigate the potential effect of the current microcode version, and we encourage customers to review their guidance on an ongoing basis to inform their decisions.
This whole thing is a mess.
After being aware of the issue for 6 months, it seems now clear that either there is no microcode solution able to solve the problem, or the solution would compromise performances so much that Intel would have to pay back customers.
I’m afraid that Intel won’t really fix the issue in current chips, a bit like with the old Pentium FDIV bug, they will insist, at first, that it won’t be a real problem in most situations.
Could Be Worst, Treza. At this moment wouldn’t like to consider the possibility of the breach allowing micro-code corruption.
They can’t and they shouldn’t. Why?
IT ISN’T A BUG.
The FDIV problem was a bug: optimization of a hardware table that failed for some numbers.
F00F was a bug: failure to detect illegal opcode that meant the hardware could reach a state it shouldn’t – resulting in halting execution.
IMO the Meltdown thing is a bug (not all think so).
This isn’t. The processor does what it was designed to do, what it is documented to do in a way that is documented. No bug.
And it’s an industry wide problem. Problem – not bug.
It’s a design flaw, which in software at least, can still be called a bug. It does do what it was designed to do, but due to an oversight, it has a security problem that no one noticed for a long period of time.
Oh, if it is not a bug, I guess it is a feature !
Not sure if you’re trolling or not.
Access to high privileged kernel-mode memory from unprivileged usermode process is not documented and it is definitely _not_ a designed behaviour.
Please, show me the description of this “feature” in architecture reference manual.
Edited 2018-01-30 22:05 UTC
That kernel mode programs can read memory read kernel memory? Download and read:
https://software.intel.com/en-us/articles/intel-sdm
Drill down into the description of how memory protection works.
But Spectre doesn’t allow that _in_the_way_the_processor_is_defined_.
Spectre v1 and v2 are not breaking protection domains.
The fact that you can establish side channel is irrelevant.
That kernel mode programs can read memory read kernel memory?
User mode programs should not event touch the privileged memory.
AMD (and others) are doing things right.
The separation of user space and kernel space has been a specified feature (Privilege levels) since the Intel 386 (possibly earlier) on the x86 architecture. Meltdown blurs the line between the two as speculative execution seems to be able to speculate with kernel space data from user mode processes and allows the speculated kernel space data to be leaked to user space. If the leaking did not occur the feature would be working as designed.
In my opinion this is a bug that requires software mitigation for current Intel CPUs and hopefully the next generation of Intel CPUs will not be susceptible to Meltdown.
This issue seems to have taken the tech community by surprise, needs to be addressed as quickly as possible due to the severity and is challenging to fix.
It is a serious problem. The best thing would be if the industry as a whole would co-operate in making processors protected against such attack.
Will not happen.
My option is also that Meltdown is a bug
But wasn’t it you was you who said No bug?
It isn’t documented, the official documentation doesn’t mention this but say that illegal accesses will cause a protection exception.
You need memory protection to _prevent unauthorized access_, not to fire-up some exceptions.
Meltdown could be implemented without Spectre-style attack, but with the help of TSX extensions.
and then noted that situations like this may result in “data loss or corruption”
The fucking irony
> This whole thing is a mess.
isn’t it just… really its embarrassing, is this industry somehow especially vulnerable to the omnishambles… its a clusterf…..
Oh well, At least computers are just a passing fad and nobody needs them for anything much…
(Advice I was given on telling my school careers officer I wanted to be a coder back in the early 90’s)
Could’ve been a cool story for the 70’s but in the 90’s this guy should’ve been kept from all children.
I 100% agree, He was in his 70’s and should have been retired… That’s why I became a qualified mechanic and only got into coding professionally 10 years ago. I’m not bitter about it though at all
No, it is instead that soon computers will be able to program themselves better than any human coder 😉
I am afraid that they opened(implemented) a ‘door’ they shouldn’t…
And the funny thing is that almost all the other CPU’s (non Intel) have some how the same feature bug too.
Very funny? 
Just wait to IME starts to show vulnerabilities…
.. its way more complex (harder to understand and get right).. and the exploits will be extremely difficult to even detect… Because the Intel IME is designed like a spyware platform.
You ain’t seen nuffin’yet.
Allow Us NOT to talk UEFI, or any kind of “firm”-ware, at this moment.