[CentOS] OT: Possible for Malware against Windows boxes to attack Firefox on Linux?

[Robert Heller]

At Fri, 17 Apr 2009 14:07:31 -0500 CentOS mailing list <centos at centos.org> wrote:

> 
> On Fri, Apr 17, 2009 at 1:17 PM, Scott Silva <ssilva at sgvwater.com> wrote:
> > on 4-17-2009 9:33 AM Lanny Marcus spake the following:
> >> On Fri, Apr 17, 2009 at 11:25 AM, William L. Maltby
> >> <CentOS4Bill at triad.rr.com> wrote:
> >>> On Fri, 2009-04-17 at 11:13 -0500, Lanny Marcus wrote:
> >>>> On Thu, Apr 16, 2009 at 11:14 PM, Michael A. Peters <mpeters-ee4meeAH724 at public.gmane.org> wrote:
> >>>> <snip>
> >>>>> My experience is that when browsing on any OS and you come across an
> >>>>> error message stating that your computer is infected and you need to
> >>>>> install such and such software, the web site I was visiting has an XSS
> >>>>> exploit that was taken advantage of to try and get you to manually
> >>>>> install a piece of malware.
> >>>>>
> >>>>> Install the FireFox extension "noscript" and be very careful about what
> >>>>> domains you authorize scripting from.
> >>
> >> I now have NoScript installed.
> >>
> >> <snip>
> >>> You might want to also check your preferences. FF has settings about
> >>> warning about fraud sites etc. You also can affect the things that
> >>> javascripts can do and suppress pop-ups. I've encountered those things
> >>> that you mentioned and gotten no ill-effects since I just leave the site
> >>> immediately.
> >>
> >> Bill: I will double check the Firefox configuration settings, since I
> >> upgraded from CentOS 5.2 to 5.3, last Friday night. I need to be able
> >> to visit that web site, so if anything bad is coming from it (without
> >> the knowledge of the webmaster) I will hopefully avoid it, with the
> >> NoScript Firefox extension which I just installed. Lanny
> >
> > Noscript will give you an idea of just how many sites run a script of some
> > kind. You will see a large part of sites just look different when the scripts
> > don't run, and some don't function at all. Not that it is a bad thing, it will
> > just make you think a lot.
> >
> >
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> >
> >
> 
> Remember the NeXT step days (for me, mid 90's) when a single
> executable binary file contained both intel and PowerPC/Motorola code.
>  When clicked, it would execute the intel code on the intel platform
> and the PowerPC/Motorola code on the PowerPC/Motorola platform.  I
> think it would be cool to have Portable App executables that run under
> both Linux and Windows because life would be easier, but the security
> problem would be too much of a downside -- a single binary that roots
> both Linux and Windows.

There is something called a StarKit that can be used to encapsulate
Tcl/Tk programs. The StarKit can be treated as an executable that will
run on any machine with a suitable Tclkit installed.  It is also
possible to combine the Tclkit with the StarKit, creating a StarPack,
which is a self-contained executable.

> 
> It is easy to write an executable binary for Linux that ends in .exe -
> so that is don't think that is any protection at all.

Linux does not care about file *names*.  A file is executable if its x
bit is set AND it is recognized as an executable.  That is one of:

1) file with the magic 'ELF' header (the # bits, bit order, and arch
have to match what your kernel can deal with)
2) a Java jar file (if you have Java installed and configured for this usage)
3) a MS-Windows executable (if you have Wine installed AND the path is
somewhere that maps to a MS-Windows drive AND Wine is configured for
this usage)
4) an ASCII file with a '#!' as its first line and the path there names an
executable file.

MacOSX also supports 'universal binaries' (binaries that run on Intel or
PowerPC processors).

> 
> Clicking "Cancel" on these dialogs or X could still launch the
> executable - safest thing to do would be to kill firefox.
> 
> Further recommend NoScript and SiteAdvisor simultaneously.  Recommend
> against wine and even more so against the Internet Explorer
> whatchamacallit for Firefox including on wine.
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>                                                                  

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