gsgi
asked on
Hooking / DLL injection
I have some applications at work that I bought.
They put information in the title bar, which we grab. This is on XP. There are two ways to do this. One involves polling to see if the title bar of the app we monitor has changed. Another involves hooking - we run a program before the apps start grab the changes to the title bar. What is dll injection? Is it hooking. To essentially become part of another app we don't have code to, do we have to have a program running?
I appreciate very much the time it takes to reply.
gsgi
They put information in the title bar, which we grab. This is on XP. There are two ways to do this. One involves polling to see if the title bar of the app we monitor has changed. Another involves hooking - we run a program before the apps start grab the changes to the title bar. What is dll injection? Is it hooking. To essentially become part of another app we don't have code to, do we have to have a program running?
I appreciate very much the time it takes to reply.
gsgi
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Well yu won't need admin privileges for a Windows hook that runs in your current session (global to that session or not), see http://msdn.microsoft.com/en-us/library/ms997537.aspx ("Win32 Hooks"). Tis also injects a DLL into all running (GUI) applicationsYou'd basically check for 'WM_SETTEXT' being sent to the handle of the window that you're monitoring. The scoop would be to
LRESULT CALLBACK HookProc ( int nCode, // hook code
WPARAM wParam, // removal flag
LPARAM lParam // address of structure with message
)
{
PMSG pmsg = ( PMSG) lParam;
if ( 0 > nCode || PM_NOREMOVE == wParam)
{
return ( CallNextHookEx ( g_hhk,
nCode,
wParam,
lParam
)
);
}
if (WM_STTEXT == pmsg->message && hWndToCheck == pwmg->hwnd)
{
/* this one is for us, so grab the new window title here */
}
return ( CallNextHookEx ( g_hhk,
nCode,
wParam,
lParam
)
);
}
>>>> Well yu won't need admin privileges for a Windows hook that runs in your current session
Is there no way to keep a trojan from installing a session hook?
Is there no way to keep a trojan from installing a session hook?
No, what happens in your session with your session's priveleges is OK (from an OS point of view).
>>>> from an OS point of view
Windows is an OS? ;-)
It is always striking to experience how many open doors a windows system has. Do you know a reason why this security hole wasn't fixed?
Windows is an OS? ;-)
It is always striking to experience how many open doors a windows system has. Do you know a reason why this security hole wasn't fixed?
ASKER
Here is the code my programmer has come up with and I appreciate any feedback, constructive critique etc. BTW I am still not clear on when you would choose the hook over either of the createremotethread techinques mentioned. i really appreciate your time and assistance and thought. As stated above my goal is for each of my user sessions on a terminal server, to capture the text in the title bar of the apps that the user is using.
The code attached seems to be working. It needs to be changed now from a dos to a background processes and tested more. Also I am curious if there is an advantage to either createremotethread technique as presented in the link provided above by evilrix.
http://files.getdropbox.com/u/1461313/Development/HookingVersion.zip
thanks, gsgi
The code attached seems to be working. It needs to be changed now from a dos to a background processes and tested more. Also I am curious if there is an advantage to either createremotethread technique as presented in the link provided above by evilrix.
http://files.getdropbox.com/u/1461313/Development/HookingVersion.zip
thanks, gsgi
ASKER
Whoops the link above was the build, here is the code:
http://files.getdropbox.com/u/1288178/TitleHook.zip
Thanks,
gsgi
http://files.getdropbox.com/u/1288178/TitleHook.zip
Thanks,
gsgi
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER
Thanks.
Installing a hook is another game. You need all admin priviliges on a system and would need to care for not opening doors to malicious programs when doing so. Moreover, spying out data from users other than yourself without the users know that they were spied out is at least questionable and may be forbidden by national laws.