Jump to content


 


Register a free account to unlock additional features at BleepingComputer.com
Welcome to BleepingComputer, a free community where people like yourself come together to discuss and learn how to use their computers. Using the site is easy and fun. As a guest, you can browse and view the various discussions in the forums, but can not create a new topic or reply to an existing one unless you are logged in. Other benefits of registering an account are subscribing to topics and forums, creating a blog, and having no ads shown anywhere on the site.


Click here to Register a free account now! or read our Welcome Guide to learn how to use this site.

Photo

Serial numbers of computers, MAC addresses, other details, any links between?


  • Please log in to reply
5 replies to this topic

#1 rp88

rp88

  • Members
  • 2,766 posts
  • OFFLINE
  •  
  • Gender:Not Telling
  • Local time:12:24 AM

Posted 10 November 2017 - 01:56 PM

I've just been wondering something recently, given either a computer's MAC address or it's serial number is it possible to look up the other?

Can you by looking at a computer (whether a laptop from a factory or a motherboard* supplied for someone to build a custom tower with) and reading the serial numbers on the labels determine what MAC address or other such connectivity details it will have? What about the reverse, from seeing a computer connect to a network (wired or wifi) and getting it's MAC address and any other details that the PC makes available to the network can the serial number be worked out? Or for that matter can a website visited in the browser see these kind of details (I'd guess this latter case to be a no)?

Are there algorithms which allow one to get either from the other (in the same way that there are algorithms like that which lets a barcode be error checked, or for that matter algorithms which calculate a sha-256 given a file)? Or is this the sort of data that a manufactuer typically keeps in logs of all the equipment they sell, but which is not predictable one-from-the-other except by the manufactuer consulting such logs? Or are things such as a computer's serial number and the serial numbers of components like the hard-drive and CPU (the sort of things that speccy can reveal for a machine it is run on) totally independent and unlinked to any identifiers it provides to networks and or websites visited?

I've just been wondering, of all the unique identifiers for any specific device how many of them are connected in some way?

Any thoughts?

*assuming the motherboard has ethernet, wifi and other connectivity stuff fitted, in effect assuming that the components to which the serial number and MAC address are tied are supplied together and not separately bought then put together by the user.

Edited by rp88, 10 November 2017 - 01:57 PM.

Back on this site, for a while anyway, been so busy the last year.

My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB

BC AdBot (Login to Remove)

 


m

#2 britechguy

britechguy

    Been there, done that, got the T-shirt


  • Moderator
  • 5,309 posts
  • ONLINE
  •  
  • Gender:Male
  • Location:Staunton, VA
  • Local time:07:24 PM

Posted 10 November 2017 - 02:04 PM

To my knowledge, the serial number of a machine and the MAC address it uses have no connection.

 

The MAC is a part of the network card (including WiFi or wired) and these are replaceable items seldom made by the companies that actually put together the components to make a computer.  The same is true for virtually any piece of hardware in a computer down to and including its motherboard.  Those can be replaced or upgraded.

 

The serial number on a given machine is just that, the serial number of that machine as a "manufactured thing" but is not connected to the serial numbers (and those exist) of its component parts.

 

I can't say anything about what may or may not be supplied to various websites, but I doubt very much that anything that's as "low level" as serial numbers are among what would be given to a random website (as opposed to, say Microsoft when you're licensing Windows 10, which does link directly to the serial number of the motherboard - which can be changed out if it were to fail but you then have to contact Microsoft to get your existing license key associated with the replacement motherboard instead of the one it was originally associated with).

 

Tracking cookies have been "the traditional way" that various sites keep track of when you've been visiting them, and those are placed on your machine by said sites and are queried on future visits.  One can, of course, put in "do not track" requests and/or purge cookies, which removes these.


Brian  AKA  Bri the Tech Guy (website address in my profile) Windows 10 Home, 64-bit, Version 1709, Build 16299

       

    Plus ça change, plus c'est la même chose
              

 


#3 Didier Stevens

Didier Stevens

  • BC Advisor
  • 2,536 posts
  • OFFLINE
  •  
  • Gender:Male
  • Local time:01:24 AM

Posted 10 November 2017 - 04:26 PM

No, in general there is no formula to convert a mac address to a serial number and vice-versa. If a link exists, it has to be documented in a database maintained by the manufacturer.

 

Also consider that a MAC address, 6 bytes, consist of 3 bytes that identify the manufacturer of the network device (OUI) and 3 bytes that are unique per network device for that OUI.

3 bytes would be a bit short to generate a serial number, unless you have short serial numbers.

 

Webservers are most of the time not on the same Ethernet segment as the client, and will thus not see the client's MAC address.

 

During a brief period of time, CPUs has a serial number that could be retrieved via the CPUID instruction (https://en.wikipedia.org/wiki/CPUID), but this is no longer supported.


Didier Stevens
http://blog.DidierStevens.com
http://DidierStevensLabs.com

SANS ISC Handler
Microsoft MVP 2011-2016 Consumer Security, Windows Insider MVP 2016-2018
MVP_Horizontal_BlueOnly.png

 

Stevens' law: "As an online security discussion grows longer, the probability of a reference to BadUSB approaches 1.0"


#4 rp88

rp88
  • Topic Starter

  • Members
  • 2,766 posts
  • OFFLINE
  •  
  • Gender:Not Telling
  • Local time:12:24 AM

Posted 12 November 2017 - 03:02 PM

Thanks for the explanations.

britechguy, extrapolating from what you said is it infact the case that the serial number corresponds to absolutely nothing. I had assumed that the serial number written on a laptop's or pre-assembled tower's case was that of the motherboard and CPU if not of anything else inside, but you seem to be saying that frankly the serial number is really just identifying the outer casing of the computer, the visible parts, while the motherboard and such are infact quite independent of this. Is this the case(no pun intended)? I guess it's one of those "grandfathers axe" things.

Edited by rp88, 12 November 2017 - 03:02 PM.

Back on this site, for a while anyway, been so busy the last year.

My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB

#5 britechguy

britechguy

    Been there, done that, got the T-shirt


  • Moderator
  • 5,309 posts
  • ONLINE
  •  
  • Gender:Male
  • Location:Staunton, VA
  • Local time:07:24 PM

Posted 12 November 2017 - 05:12 PM

rp88,

 

         Essentially what you say is true, with the exception of the computer's serial number on the case just identifying the case.  It identifies the computer as a single instance of its make and model as a whole.  The manufacturer knows quite well (or often does - as this allows them to identify tampering that would void warranty) what serial numbers of the various component parts were assembled to make the whole computer.  

 

         The serial number of a computer is not unlike the VIN of a car.  A car is assembled of many, many component parts, many of which have their own serial numbers, but the VIN identifies a completed instance of the automobile (or, more generally, vehicle).  This is common practice for virtually any item assembled of myriad parts:  their serial numbers identify a single instance of the completed product.


Brian  AKA  Bri the Tech Guy (website address in my profile) Windows 10 Home, 64-bit, Version 1709, Build 16299

       

    Plus ça change, plus c'est la même chose
              

 


#6 rp88

rp88
  • Topic Starter

  • Members
  • 2,766 posts
  • OFFLINE
  •  
  • Gender:Not Telling
  • Local time:12:24 AM

Posted Yesterday, 12:44 PM

Thanks
Back on this site, for a while anyway, been so busy the last year.

My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users