Time
2 hours 52 minutes
Difficulty
Intermediate
CEU/CPE
3

Video Transcription

00:00
Welcome back to Printing Security Intermediate Course. In this lesson, I'm going toe talk about PCL five paper definition language and how can you have a printer with P C. L's in general,
00:15
So
00:17
PCL five uses escape sequins. Common commands so means that if you're sending just the plain text file on the PCL printer, providing that you have a head there and other things that are necessary for modern printer to understand what you're trying to do with a print job.
00:37
So if you create a text sprint job with just the text and Heather,
00:41
uh, it will print that text like like a regular old style that metrics printer, of course, using default phone to defined by
00:50
the device, which is set on the device itself on and
00:56
basically a printing default. So resolution and everything else is going to be set to printing default.
01:03
Now, if you want to change something like, for example, you want to change the resolution Human to set the resolution to be 600 by 600 dp I or you want to use some kind of resolution enhancement technology that modulates the size and the position of the dot on the paper to get the crisper output,
01:22
um, or you want to add some graphics. Then you have escape sequences, which you start with a ski 27 character.
01:32
And then what follows? That escape character is basically a PCL five command and then printer interpreted the command
01:44
in the way it is defined in the description of the Printing PCL language. It's not a real programming language, so there is quite the limitation of what it can do.
01:57
And the process off Processing PCL five document print file in the printer is called Parsing, So you are not running it like a regular print language is just that. The software inside the printer, which is
02:12
PCL five part sir, is looking at commands and putting something in the memory
02:17
that, ah,
02:20
we'll be later transferred into dots on the paper.
02:24
So in generally, if you have PCL, regardless of aversion, how do you hack with it? Well, you can intercept and alter
02:32
print jumps, or you can create malicious prince files by yourself,
02:38
and what you can do is essentially change the white settings. Now these changes can be serious. For example, you can do a device reset so that whatever is in, ah, devices, memory can be deleted. Uh, although it's usually done with P J L not with PCL,
02:58
but you can do, For example, you can change the message that is on a display, which says, Ah, error device users basic. Put it in the port. Whatever. And that way you can fool a user to hack a device or something like that.
03:15
And if you want to look more into PCL hacking, you can download the practical, which is essentially a reference for printing, hacking Using PCL. You have the address here, you can download it, install it and play with it and see how it's done.
03:32
So in this video, you have learned that what are the specifics of PCL five and what can you do if you want to hack a printer using the seals
03:43
in next lesson, I'm going to talk about PCL six and the differences between PCL six MPC or five

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Intermediate Printing Security

The Intermediate Printing Security course is intended for IT and cybersecurity professionals that want to learn how to secure print devices.

Instructed By

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Milan Cetic
IT Security Consultant
Instructor