On 09/26/2011 12:26 PM, rohan puri wrote:
On Mon, Sep 26, 2011 at 12:02 PM, Abhijit Pawar
<apawar.li...@gmail.com <mailto:apawar.li...@gmail.com>> wrote:
On 09/23/2011 03:11 PM, rohan puri wrote:
On Fri, Sep 23, 2011 at 2:43 PM, Abhijit Pawar
<apawar.li...@gmail.com <mailto:apawar.li...@gmail.com>> wrote:
On 09/23/2011 02:04 PM, rohan puri wrote:
On Fri, Sep 23, 2011 at 2:00 PM, Abhijit Pawar
<apawar.li...@gmail.com <mailto:apawar.li...@gmail.com>> wrote:
On 09/23/2011 01:01 PM, Rajat Sharma wrote:
Untidy way : -
Yes, you can do that by registering a new binary
format handler. Whenever
exec is called, a list of registered binary
format handlers is scanned, in
the same way you can hook the load_binary&
load_library function pointers
of the already registered binary format handlers.
Challenge with this untidy way is to identify the
correct format, for
example if you are interested in only hooking ELF
format, there is no
special signature withing the registered format
handler to identify
that, however if one format handler recognizes the
file header, its
load_binary will return 0. This can give you the
hint that you are
sitting on top of correct file format. Long time
back I had written
the similar module in Linux to do the same, but
can't share the code
:)
-Rajat
On Thu, Sep 22, 2011 at 3:14 PM, rohan
puri<rohan.pur...@gmail.com
<mailto:rohan.pur...@gmail.com>> wrote:
On Thu, Sep 22, 2011 at 1:53 PM, Abhijit
Pawar<apawar.li...@gmail.com
<mailto:apawar.li...@gmail.com>>
wrote:
hi list,
Is there any way to hook the exec system
call on Linux box apart from
replacing the call in System Call table?
Regards,
Abhijit Pawar
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Tidy way : -
You can do that from LSM (Linux security module).
Untidy way : -
Yes, you can do that by registering a new binary
format handler. Whenever
exec is called, a list of registered binary
format handlers is scanned, in
the same way you can hook the load_binary&
load_library function pointers
of the already registered binary format handlers.
Regards,
Rohan Puri
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So If I use the binary format handler, then I can hook
the exec call. however I need to register this. Does
that mean that I need to return the negative value so as
to have actual ELF handler to be loaded?
Regards,
Abhijit Pawar
Read this,
http://www.linux.it/~rubini/docs/binfmt/binfmt.html
<http://www.linux.it/%7Erubini/docs/binfmt/binfmt.html> this
might help
Regards,
Rohan Puri
Thanks Rohan. I tried creating a hooking module on the
similar line. I am able to load the module but whenever I am
launching any application , its load_binary is not being called.
here is the source for the module attached.
Regards,
Abhijit Pawar
Hi Abhijit,
I have made the change, try to compile and execute this code, it
works.
Also, I am just curious enough to know that where do you need to
do this hooking.
Regards,
Rohan Puri
Hi Rohan,
I have been looking at Windows worlds ability to support DLL
Injection and API hooking. I was just wondering if this could be
something to be done in Linux as well. I am not sure if there is
any special use of this module apart from learning the binary
handler. May be it could be used as a security module for your own
binary handler.
Regards,
Abhijit Pawar
Hi Abhijit,
I am not familiar with windows. Special use-case of this hacking is
for security companies whitelisting software solutions, where they
want to control execution of only authorized binaries on the system
and deny the execution of others.
Although this approach is untidy, since there is available LSM hooks
in linux kernel which needs to be made use of for doing this.
Regards,
Rohan Puri
Hi Rohan,
Yes, this is a backdoor approach and I agree with you. I am learning
more on LSM and their APIs so as to get insight into what goes on
internally. May be you can refer me to some details as well.
Thanks for all of your help on this.
Regards,
Abhijit Pawar
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