Airscanner Mobile Security Advisory     ==  PRESS RELEASE ==

*Title*

Virus exploits workaround in Windows Mobile/Pocket PC architecture (Includes Source 
Code)

*Introduction*

Airscanner Corp. has obtained and published the complete, annotated source code to 
CE.Dust, the first virus to infect the Windows Mobile/Pocket PC platform.

*Background*

Virus authors have been trying to infect Windows CE for several years. However, 
CE.Dust had to overcome unique technological barriers in order to infect this 
platform. By publishing the source code, Airscanner Corp. hopes to help security 
researchers and programmers develop appropriate countermeasures.

Airscanner Corp. received the CE.Dust virus from its author at the exact same time as 
all other major antivirus companies. However, because Airscanner Corp. specializes 
exclusively in  software reverse engineering for ARM-based processors, we were 
fortunate enough to be the first antivirus company to analyze the virus and post a fix 
on July 16, 2004:
http://www.airscanner.com/pr/dust0715.html

*Source Code*

Following our initial publication, we wrote to the virus author and asked him to 
explain how he managed to be the first to infect this virgin OS. He was kind enough to 
explain his results in great detail. We have published his source code, along with 
annotation and our background material, at the following link:

http://www.informit.com/articles/article.asp?p=337071

*Vulnerability*

The virus exploits a unique workaround in the Windows CE.NET security architecture. 
Windows CE was designed with a protected kernel. User-mode applications are not 
permitted to interact directly with the kernel. This was designed to enhance the 
security and stability of Windows CE.

However, the "coredll module" resides deep within the kernel. This is the key module 
that controls all of the core system processes -- as well as all of the necessary ingredients 
for sucessful virus infection.

The CE.Dust virus exploited a clever workaround of the operating system architecture in order to 
gain access to the coredll module. Specifically, in Windows CE.Net, Microsoft has left the 
function "kdatastruct" acessible to usermode. This provided the key to the entrypoint 
of the virus. Full details of this vulnerability are provided in the annotated comments of 
source code listed in the article above.

*Contact*

Airscanner Corp.
http://airscanner.com/
[EMAIL PROTECTED]

Contributors:

Cyrus Peikari
Seth Fogie
Ratter/29A
Jonathan Read






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