Lodi <> wrote:
> A few days old but still interesting.....
>
> <snip>
> Security experts are warning now about a new Trojan horse released in the
> wild, targeting OS X Tiger and Leopard users. The malware can steal your
> passwords, avoid detection, log what you type and even take your picture.
>
> If the latest malware alert is any indication, Mac users may be forced to
> re-think their relaxed approach to online security [...] Unlike previous
> malware attempts that often were proof-of-concept releases, this beast
> can cause real damage
> </snip>
>
> http://www.tgdaily.com/content/view/38088/108/
>
>
> I thought Mac had the same "virus protection" structure as Linux, i.e
> anti-virus software not really needed cos of the root/admin password and
> the directory structure. I've never used a Mac so would appreciate any
> further info.
First, this isn't a "virus". Viruses spread automatically, by making use
of remotely exploitable security holes in operating systems, and once
installed they attempt to spread to other computers. This particular
software has none of those characteristics.
The underlying problem is one particular application included on Mac OS
X which is configured to run as root (via setuid, for those who
understand Unix), and it is also scriptable via AppleScript. This means
it can be told to execute an arbitrary shell command with root
privileges.
This is a major blunder on Apple's part, and something they will
certainly be fixing in the next OS release and/or security update.
This security hole can only be exploited by something running on the
computer locally (AppleScript requires the GUI to function), so it is
not exposed to a typical "virus" distribution method.
It is exploitable by any user on the computer, not just one with
administrator privileges, so even a temporary "guest" account on the
computer with no knowledge of passwords can gain root privileges with a
one line command if they know the details.
If you don't have physical access to the computer, the only way this
problem can be exploited is via a trojan horse, where you are basically
tricking someone into installing software which does something other
than what it claims to do.
> Admittedly you've got to be dumb enough to download and execute this 3MB
> virus but if a Mac can be infected what's stopping the mighty penguin
> being targeted via the same method. The MS fans will be loving it.
Any Unix-based system could potentially be exposed to this type of
trojan horse IF there is any software on the computer which is
configured to execute with root privileges (using the setuid bit), and
it has means to execute arbitrary code or has some kind of bug like a
buffer overrun which can be exploited to execute arbitrary code.
This particular case is unique to Mac OS X, because the software in
question with the security hole is only supplied with Mac OS X, not
other Unix or Linux systems.
The problem with Windows exposure to viruses is due to a significant
number of bugs which can be exploited remotely. Even as Microsoft finds
and fixes them, there are enough computers out there which aren't being
kept up to date with the latest patches that viruses still have a good
chance of spreading widely.
This sort of issue with remote exploits is rarer on Mac/Unix/Linux
systems (compared to Windows), and on the occasions where there is a
remotely exploitable problem, the relatively low proportion of
Mac/Unix/Linux systems in the world helps to limit the potential scope
of viruses spreading.
I'm not aware of a single virus that has ever existed "in the wild" for
Mac OS X. There have been a few trojan horses, but they have mostly been
proof of concept, or don't get very far.
--
David Empson