Microsoft Updates to Meltdown (CVE-2017-5754) seem to have accidentally left users using systems exposed Windows 7 64-bit. Τα συγκεκριμένα συστήματα φέρεται να είναι ευπαθή πολύ περισσότερο από ότι ήταν πριν την information, according a researcher.
Let's remind that Meltdown is a hardware vulnerability that proved almost simultaneously by several groups of researchers.
The vulnerability allows an attacker to access the contents of kernel memory in passwords and encryption keys, that is, from a part used by routine applications.
So Microsoft and many other companies tried to fix the vulnerability by updating operating systems (except for BIOS updates from manufacturers). So we saw two different updates for Windows in January and February.
But according to Ulf Frisk, something went wrong right from the first update version που κυκλοφόρησε τον Ιανουάριο, όταν εγκαταστάθηκε σε συστήματα με Windows 7 και Windows Server 2008 R2. The update skipped some control permissions for something called Page Map Level 4 (PML4).
What is this;
Είναι ένας πίνακας που χρησιμοποιείται από τους μικροεπεξεργαστές της Intel για να μεταφράσει τις εικονικές διευθύνσεις μιας διεργασίας σε διευθύνσεις physicsς μνήμης στη μνήμη RAM.
However, only the kernel must have access to this table. Because if things do not happen, they are very simple for every attacker.
No clever exploits will be needed, since Windows 7 does all the hard work of mapping the required memory to each running process. The exploit is simply a matter of reading and writing to an already mapped one virtual memory in operation. No complicated APIs or syscalls required.
According to Frisk, the update was released on March Microsoft has fixed the problem on Windows 10, 8, and 7 32bit. This means that Windows 7 x64 systems that receive only the January and / or February updates are still affected.
Seeing systems more vulnerable (than they were before) after an update security it's something we don't come across often.
First there was an update on the flaw, which created a new and distinct defect, which required a new solution for repair.
But to be fair, Microsoft may have written the buggy code, but it was trying to cover completely security flaws that originated in the way hardware was designed two decades ago.
Following the above, we must once again emphasize the importance of immediately implementing any new updates.
OK with Microsoft good will be to wait a few days, especially in production systems.
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