2 vulnerabilities combine to auto execute received files in Nokia series 60 OS

[rohit () kritikalsolutions com]

Hi,
 I forwarded this bug to Nokia security group, they believe it is a
feature and not a bug. Whats your opinion?
> > >
1. By default, executable files cannot be transferred (many mobile game
companies probably earn their bread because games are not transferrable
from one phone to the next). But if you rename the file (install file) to
any extension such as jpg or an unknown extension, it can be transferred!
So if i need to transfer a virus, all i need to do is rename the file to
some jpg extension and and transfer it!

2. When series 60 OS receives such a file, it executes it immediately. For
example, in case a MMS message comes with a picture or an installer
attachment, Nokia would immediately start running the attachment. This is
a major design flaw.
Imagine a virus, renamed as a .jpg (mobile wall paper) is downloaded by
users on p2p networks or from a website or can come from a friend. Virus
installs  itself and than shows a jpg file, so user does not suspect
anything, while he is now infected. This is than sent to everyone in the
address book, who again just see the wall paper after a prompt, while the
virus has installed itself.

The first problem can be used to exchange mobile games and ring tones for
free. When you try to transfer the same without renaming, the OS does not
allow transferring them.
Thanks
Rohit Dube
New Delhi.

Nokia response to both the problems follows:

Hi Rohit,

Sorry for the delay answering back to you.

About your findings, the first one with sending files after changing the
extension is a known limitation of the current implementation. We also
implement OMA DRM 2 which will work as expected in such situations.

The second one is also know feature, the file type is not determinated
from the extension but from the content of the file. So a sis package
renamed to an jpeg file still looks from the inside as a sis package and
so the user is prompted for installation.


Thank you again for your report.

tatu


> -----Original Message-----
> From: ext rohit () kritikalsolutions com
> [mailto:rohit () kritikalsolutions com]
> Sent: Tuesday, January 18, 2005 04:17
> To: Mannisto Tatu (Nokia-TP-PST/Tampere); Ahlberg Janne
> (Nokia-M/Tampere)
> Subject: RE: series 60 os auto executes files
>
>
> Hi Tatu, Janne,
>  Any information on this vulnerability? Can you please confirm your
> findings and send me an update on when should I/we disclose it?
> Thanks
> Rohit

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