Date: Mon, 11 May 2015 18:15:30 +0300 From: Shinnok <admin@...nnok.com> To: john-dev@...ts.openwall.com Subject: Re: [core john] [Johnny] Windows event loop > On May 11, 2015, at 4:45 PM, Mathieu Laprise <mathlaprise@...il.com> wrote: > > Shinnok said: > Mathieu, I'm not sure you have been exhaustive enough in assertions regarding the exploitation of the CTRL_ events. > > What we know: > > 1. We can signal CTRL_ events to JtR on Windows with GenerateConsoleCtrlEvent. (#ifdef'ed of course) https://msdn.microsoft.com/en-us/library/windows/desktop/ms683155(v=vs.85).aspx <https://msdn.microsoft.com/en-us/library/windows/desktop/ms683155%28v=vs.85%29.aspx> > 2. We can ignore CTRL_ events in Johnny by doing: > " • Calling SetConsoleCtrlHandler with the NULL and TRUE arguments causes the calling process to ignore CTRL+C signals. This attribute is inherited by child processes, but it can be enabled or disabled by any process without affecting existing processes." https://msdn.microsoft.com/en-us/library/windows/desktop/ms686016(v=vs.85).aspx <https://msdn.microsoft.com/en-us/library/windows/desktop/ms686016%28v=vs.85%29.aspx> > 3. We can re-enable CTRL_ events back in JtR. Simple patch to core. > 4. Verify in signals.c that JtR does indeed kill itself upon doing that for Windows. > 5. Hail that we don't have --fork there. > > Let's focus on CTRL_C_EVENT until we have reason to do otherwise. > > I tried this solution a few days ago which is based on KingDragon( http://stackoverflow.com/questions/813086/can-i-send-a-ctrl-c-sigint-to-an-application-on-windows <http://stackoverflow.com/questions/813086/can-i-send-a-ctrl-c-sigint-to-an-application-on-windows>) but as I stated at the end of this answer http://www.openwall.com/lists/john-dev/2015/05/08/16 <http://www.openwall.com/lists/john-dev/2015/05/08/16>. > > So, sending event CTRL_C_EVENT or CTRL_BREAK_EVENT, both call > sig_handle_abord(SIGINT) which will handle cleaning or other stuff needed > by John like if it was from the tty. So john saves its state. > However, in my tests, I got the same result as Shaktra(from the same stackoverflow article) for CTRL_C (returned true but wasn't sent). Here is what he said on stackoverflow. > > > It is very important that each step is done like this. I've been trying > > all different kinds of combinations but this combination is the only one > > that works. You can't send a CTRL_C event. It will return success but will > > be ignored by the process. CTRL_BREAK is the only one that works. Doesn't > > really matter since they will both call ExitProcess() in the end. (EDIT by > > me: In our specific case, we reimplemented the handler so > > sig_handle_abort_ctrl() will be called before) > > Have you tried DetachConsole first then Attach? Some people say that fixes their problems. My gut instinct after reading about this is that the CTRL_ events are only supposed to work from inside the Windows Console Application, but then that doesn't explain why it works via the intermediary process method. Shinnok Content of type "text/html" skipped
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