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• #96 S_x96x_S őstag Jack@l #45

  Új Válasz 2018-01-03 13:35:17 #96

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  válasz Jack@l #45 üzenetére

  > Kettővel feljebb írtam le mért hülyeség amit mondtál,

  nem értelek, ki tudnád jobban fejteni - Melyik része is a hülyeség?
  Egy másik ismert sérülékenységgel ami lehet egy eddig nem ismert web browser bug is simán galyra lehet vágni a gépet, és ez imho: nem csak a virtual machine (VM) -ban futtatott programokat érinti.

  Elég sok következménye van a dolognak, legalábbis ez az én értelmezésem és most még csak a dolgok felsznét kapargatják.

  "The mysterious case of the Linux Page Table Isolation patches"

  Virtual memory is possibly the single most important robustness feature in modern operating systems: it is what prevents, for example, a dying process from crashing the operating system, a web browser bug crashing your desktop environment, or one virtual machine running in Amazon EC2 from effecting changes to another virtual machine on the same host.

  "Over at this year’s CCC, you can find another of the TU Graz researchers describing a pure-Javascript ASLR attack that works by carefully timing the operation of the CPU memory management unit as it traverses the page tables that describe the layout of virtual memory. The effect is that through a combination of high precision timing and selective eviction of CPU cache lines, a Javascript program running in a web browser can recover the virtual address of a Javascript object, enabling subsequent attacks against browser memory management bugs.

  So again, on the surface, we have a group authoring the KAISER patches also demonstrating a technique for unmasking ASLR’d addresses, and the technique, demonstrated using Javascript, is imminently re-deployable against an operating system kernel."

  http://pythonsweetness.tumblr.com/post/169166980422/the-mysterious-case-of-the-linux-page-table

  http://www.theregister.co.uk/2018/01/02/intel_cpu_design_flaw/
  "Impact
  It is understood the bug is present in modern Intel processors produced in the past decade. It allows normal user programs – from database applications to JavaScript in web browsers – to discern to some extent the layout or contents of protected kernel memory areas."

  "How can this security hole be abused?
  At best, the vulnerability could be leveraged by malware and hackers to more easily exploit other security bugs.

  At worst, the hole could be abused by programs and logged-in users to read the contents of the kernel's memory. Suffice to say, this is not great. The kernel's memory space is hidden from user processes and programs because it may contain all sorts of secrets, such as passwords, login keys, files cached from disk, and so on. Imagine a piece of JavaScript running in a browser, or malicious software running on a shared public cloud server, able to sniff sensitive kernel-protected data."

  Mottó: "A verseny jó!"

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