Thursday, March 19, 2009

What did they take when they left? Part 1 - Detecting CD Burning

Dear Reader,

We've been discussing server level analysis for the last couple posts but there is plenty to talk about on the desktop. This will be a multi part series discussing different artifacts that we can recover that give us provable facts regarding a user's activity. It is easy to speculate on actions based on speculative data such as access data or related files or dll's accessed on a system but it is always better to rely on a repeatable process that creates a specific artifact each time to explain a user's action.


We only do cases that either lead to civil litigation or are in the process of civil litigation (no criminal work). One of our most common requests is the question, before this employee left did they take any documents with them. There are several places on a system we check to determine if a user has taken a document from the system in some fashion (CD, USB Drive, Emailed out, printed, etc…) and in this post we will discuss how to determine if a user has burned a CD. If you are examining a Windows XP or Windows Server 2003 (I have not been able to test this on Vista or server 2008 yet) image then the system event log will contain eventids 7036 and 7035 as it was generated by the Service Control Manager and will contain in the description a string starting with The IMAPI CD-Burning Service. There will be one such set of entries showing the service starting and stopping on each reboot but any entry not close to a reboot will indicate that a CD is being burned from this system.


An example of a burning entry, yes my machine is named HOSS:

12/11/2008

3:04:13 PM

Service Control Manager

Information

None

7036

N/A

12/11/2008

3:04:13 PM

Service Control Manager

Information

None

7035

NT AUTHORITY\SYSTEM

12/11/2008

3:04:22 PM

Service Control Manager

Information

None

7036

N/A

HOSS

The IMAPI CD-Burning COM Service service entered the running state.

HOSS

The IMAPI CD-Burning COM Service service was successfully sent a start control.

HOSS

The IMAPI CD-Burning COM Service service entered the stopped state.

Sorry for the bad editing here, the full row will not fit in this blog template. The line starts with the date and then continues in the block below. There is one date for each of the IMAPI entries.

If those three entries are not part of a reboot/startup sequence then you have found a user burning a CD. These entries do not have to be in uninterrupted sequence as you see here, but there should be a start and a stop to show a successful burn. This is not just for CDs burned by Windows directly, third party applications will also call this service when burning a CD. You can estimate the size of the data burned to the disk by determining the number of minutes spent burning (the time between the start and stop of the service) multiplied by the write speed of the CDROM. This also applies to DVDs.


I will not discuss how to determine if a CD was accessed in this post as that is material for Part 2 – What was accessed from external drives.


Update: As per the comments below, more activities than just booting and burning will cause these event log entries to show up. I will be doing some more testing to find a better answer.

13 comments:

  1. Good series of articles.
    I'm finding that the 3-IMAPI System Event log entries occur during various stages of the burning process.

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  2. Agreed, in the future i plan for a larger test set to see what all happens with various quantities of data being burned.

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  3. "If those three entries are not part of a reboot/startup sequence then you have found a user burning a CD"

    Not entirely true. I have seen on some XP systems these 3 entries show up when you merely insert a CD, whether it is blank or not. In my experience, it is more indicative of a burn if these entries are separated by a minute or longer, i.e. the time it took to burn.

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  4. Hi Greg,
    That didn't happen in my testing but I need to do more testing to get more examples. Can you tell me what software you had loaded? Maybe the program associated with the drive is starting the service? I didn't have any such program loaded on my test systems.

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  5. Question about the calculation of the size of data burned from the example above...

    Since it was 9 seconds, would it be:

    .9 x 24 (assuming it was a 24x burner) = 21.6mb ?

    Thanks, great blog

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  6. It was 78.6mbs that I burned. In order to generate a more accurate test to determine data burned to the megabye we would need to try out different burners and see where in the process the service starts.

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  7. I should mention that I burned a dvd in this example which might explain the variance

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  8. "If those three entries are not part of a reboot/startup sequence then you have found a user burning a CD"

    I have to dissent on that, In fact if you open Windows Media Player, as soon as you click on the "burning tab", you'll see the first two entries in the event log, then you can switch to the player tab and listen to your mp3's and finally when you close your media player you'll see the last entry. So according to your statement I should have burned a CD, but in fact I had none.

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  9. Hi Clarity seeka,
    Agreed, the other comments also suggest as such. I am going to go back and do more testing to see what else we can determine and then I'll make an update entry with the results. Thanks for commenting.

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  10. I recently came accross your blog and have been reading along. I thought I would leave my first comment. I dont know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often.

    Joannah

    http://keyboardpiano.net

    ReplyDelete
  11. "Hi Greg,
    That didn't happen in my testing but I need to do more testing to get more examples. Can you tell me what software you had loaded? Maybe the program associated with the drive is starting the service? I didn't have any such program loaded on my test systems."

    Sorry it took me so long to reply...

    It has been a while since I tested this but if memory serves me well, I tested this on a computer that had Roxio's EasyCD Creator and one that just had the built in Windows XP burning software.

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