Linked by Alcibiades on Wed 4th Jan 2006 18:04 UTC
Windows Like a lot of people who have worked in the business, I find myself in conversations about computer security with people who are having problems or know people who have problems. I wrote this to save me from explaining the same thing over and over again to different people, and to save them the trouble of having to make notes as we talked. It was meant to be something you could give to a 'naive user' and have them be able to read and follow it more or less unaided, and while not being a complete guide, at least be something that made them more secure than before they got it.
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RE[2]: Zonealarm
by yawntoo on Thu 5th Jan 2006 15:53 UTC in reply to "RE: Zonealarm"
yawntoo
Member since:
2006-01-04

Yes you can do this, however you need to have permission to access the other process in this way.

On Windows, the way you do this is to:
1) Open a handle to the target process
2) Allocate memory in the other process space
3) Write the path to your DLL into that memory space
4) Create a thread in the target process space with the thread proc set to LoadLibrary and the parameter set to the memory address you allocated in step 2.
5) Your dll code is now running in the other process...

This is a very well known DLL process injection attack. The OS APIs used for this attack exist to allow debuggers to function (among other things). This is just an example of how powerful tools can be used for good and for bad.

A few things to keep in mind with this attack:
1) You can be attacked in this way even if you are not running as administrator. The attack can simply choose to inject into a process that your user account owns.... like iexplore.exe.
2) You cannot inject into a process if you don't have permission to open the process and create remote threads. This would prevent even the administrator from attacking processes owned by the system without doing a bit more work.

I haven't really looked into this style of attack on Mac OS X, or variants of Linux, however I wouldn't be surprised to find that a similar attack is possible. For Mac OS previous to OS X and Windows 9x/ME/3.x would probably be rather easy to attack. IIRC they lacked protected memory so any process could access another process's memory space.

There are plenty of sources on the net that describe this sort of thing. See www.rootkit.com for some examples.

Edited 2006-01-05 15:55

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