Time
3 hours 35 minutes
Difficulty
Intermediate
CEU/CPE
4

Video Transcription

00:00
hello and welcome to P C Security Intermediate course.
00:04
In this lesson, I will be talking about a very important part off PC. That is, from security point of view, extremely important, which is unified bias.
00:15
And in this video I will be talking about what the your if I is on what is its role in the way the PC works and how the unify is impacting the security of PC, or how can it be used to manipulate the
00:34
BC?
00:36
So first question for you is what is you If I bias
00:40
your phone bios, by definition is called is an acronym from Unified Extensible Firmer Interface,
00:49
and it's essentially designed to be some kind of middleware or middleman between OS and the hardware. So you have hardware. If you have been listening the previous lessons, you have harder components like processor like hard drive like
01:06
input output, trips on a mother board
01:08
and these components that have their own firmer. And when you put the machine, this firmer starts and
01:17
it runs all the time in the small micro processes on these components.
01:22
Now you if I is there to come away, let's say the orders from the operating system and transferred to those components and give it in the format that this firmer can understand. So this is essentially the cure buys does.
01:38
It's much more complicated, and it's not always like that. And sometimes applications can communicate directly with components, and
01:47
it's really, really, really complicated thing. But this is essentially what the U. F five buyers was created for.
01:56
Three idea behind the U. F I buyers. Just to make it a little bit more understandable for you is that
02:04
you have the harbor and you have the processor the part of harder. And if you make the U F I buyers some kind of standardized platform,
02:14
then you can essentially build the operating system on the PC. Absolutely, regardless off the command set that the process there is using. So you can use
02:25
completely different type off Ah, processor, and then, if you if I written to certain standards, then you can build the operating system on top of that,
02:38
and you don't communicate with the process, Er told you, Just communicate with bias so buyers can represent some kind of fun.
02:46
And
02:47
with a layer between the hardware and the firmer, which makes ha operating system harder. Agnostic,
02:55
This is not happening today. So this is not the case. You still have to write the operating system so it can run on a certain type of processor. For example, if it runs on Intel architectures, er,
03:08
it cannot Friend on arm and so on his own. So
03:13
But most of the things you do from the operating system in order to communicate Teoh hardware, you can do through some kind of calls. 32 year five functions
03:23
how it looks in a PC.
03:25
So you you plug your for power on the PC,
03:30
and the first thing that happened is that
03:32
it starts device firm herbal closures, and then devices they get their firmer booted, so it's a first level.
03:43
The second level is that, uh oh, am Yueh Fei and unify applications get started
03:53
and these things get booted they started and
04:00
the next thing that is getting started these Windows book managers so Windows book manager is being started from within Dio if I unify bias So when you start to PC when device firmer book loaders load which is happening in where short period space,
04:15
then, um some unify application started. This is a thing that you see sometimes on a PC. When you boot it up, you see that message press escape or press F two or press F time to enter the by the set up.
04:30
So this by set up and this message you see, it's actually in the application that transmitting the you if I bias,
04:39
which gives you the opportunity to set some perimeters off perimeters off to some settings in unify bias.
04:46
So all these things are run within the U. F I
04:50
and then Windows boot manager actually boots the window standing to memory,
04:58
and then you're a braking system starts and you get the
05:01
the message that windows is boating, and then you
05:08
you you have your logging screen.
05:11
The similar thing is happening if you're using math course ***, so
05:15
it's pretty much the same.
05:18
What is important is that you if I has the highest privilege in the PC.
05:23
So some, for example, programs. They have the lower privilege, and they cannot taxes some things. But you if I can essentially access everything,
05:32
so you have all these horrible components that I have been talking about, and then you have a firmer
05:39
off these components, and this is This is like first half a second of second when you boot the PC
05:46
and then you load that you if I
05:48
and you. If I then the reserves a piece of memory for itself,
05:53
which is not, then it's not letting the operating system access that part of memory. So operating system is excluded from accessing the part of memory.
06:02
Daniel Boulud the operating system,
06:05
which has a very high privilege on a PC. But it's lower than you if I so it cannot access something's on a PC
06:15
without
06:15
essentially asking the If I can, you give it to me. And if it's something in the memory of your if I
06:21
the answer will be no,
06:24
it's a simplified way of explaining it, but
06:28
just for you to understand easily and then you have programs on application. So there are, for example, sometimes in the operating system that programs and applications that run on the operating system should not be able to access is well, and they are accessible to operating system.
06:43
So you have understood so far that unifies like a small operating system. It operates outside the reach of operating system.
06:50
You have the unify applications that run under you. If I, for example, one typical your unify application, is by a set up utility
06:59
in which you can set the
07:01
do the settings off, for example, from which drive you're putting. First, the operating system you can have. You know, four or five hard drives in the B C,
07:14
and you can set which one is going to be the one on which the operating system actually is, are you? And you can boot from that one? Or you can have four drives with four different operating systems on it,
07:26
and then in bias, you can choose from which one you want to boot
07:30
and sometimes always reaches harbor through you. If I So, for example, of if you type something on a keyboard,
07:39
it has essentially gets through you if I and goes into operating system. So even if you're typing your let's a password
07:46
on, do you see only the dots on the screen and said the characters unify knows what you have been typing. Actually, the operating system knows that as well, but
07:58
this is the point. There are some things that operate the system doesn't see but by a season.
08:05
So this is you. If I I will continue talking about why is your if I so important and what can it ban Bill it? But now you understand that you have five, essentially has the control over your PC.
08:16
You if I cannot to do things like browsing. There is no application unified that can let you browse Internet because this is high level programming and bias. The unify bias is not that big. In order to incorporate full.
08:35
What's a Web browser that can dual the functions off the VEB Rosa's you have within the operating system?
08:41
So some of these things you if I doesn't do but what it can do and what it does it you can see everything so we can look in every file in your hard drive can look the content of your memory.
08:56
Essentially, all of that is within the bias. It can also see whatever is coming through your network
09:05
fort.
09:07
Okay, so this video you have learned about what is you find what is it throwing PC? And in next lesson, I'm going to continue elaborating on this topic

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Milan Cetic
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