Some news
 Piotr Bania (Piotr) <bania piotr gmailcom> |
Tuesday, August 30 2005 12:19.45 CDT |
Lo,
After 2 days of work I'm finishing my polymorphic decryptor generator, i'm planning to end in later this week. Currently 80% of it is done, i just need to end instruction-block-mixing engine and some garbage generator (copro instruction etc.). I have done it to generate some poly decryptor for shellcodes (currently it is some NULL avoiding), however it can be good for other cases.
It should be a Level 4/5 engine, decryption will be based on the CPU time (some anti emulators things) also the decryptor itself will be used as decryption key together with part of uncoded data (no breakpoints on decryptor, this may confuse some emulators). Decryptor size is no const, the decryption step is calculated randomly from 1-5 bytes. Here it is probably better to use complete nonlinear decryption, for example like Mental Driller does (yeah, PRIDE technology with BRANCHING kicks ass) and also do some substitution cipher like in W32.Chiton (xlat etc.). I have no idea how NIDS emulator work (i mean if they are really trying to emulate the decryptor not only search for NOP regions etc. etc.) because i have none of them, but appending to NGSEC paper it is possible.
Ok, now I need to take a walk :)
laters,
Piotr Bania
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| Posted: Wednesday, December 31 1969 18:00.00 CST | |