As far as I know, driver is used to be an interface between OS and hardware.

Both Duqu and Stuxnet use a kernel driver to decrypt and load certain encrypted files on the infected computer. The kernel driver serves as an "injection engine" for loading the files into a specific process, according to SecureWorks. "The kernel drivers for both Stuxnet and Duqu use many similar techniques for encryption and stealth, such as a rootkit for hiding files," the security vendor said in its report.

from:
http://news.idg.no/cw/art.cfm?id=A0D...F48A30CE1D5495

1-What is the kernel driver?

2-I read the article in wikipedia for DLL injection and it makes no sense, May someone tell me about it?What is difference between DLL injection and process injection?

Thanks in advance