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Date: Mon, 25 May 2015 05:55:50 +0300
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: Fuzzing Report on wordlist, rules, chr

Kai,

On Mon, May 25, 2015 at 09:57:50AM +0800, Kai Zhao wrote:
> 3. Fuzz chr
[...]
> Command:
> afl-fuzz -t 1500+ -m none -i input_cases/ -o out -f fuzz.chr ../john ppww
> --nolog --skip-self-test --format=md5crypt --incremental=Lanman
> --config=local.conf --max-run-time=1

You could have increased the coverage of this test a little bit by using
a faster hash type, such as dummy, raw-md4, NT, or LM (indeed, your
"ppww" file should contain a hash of that type).  It would then proceed
much further in incremental mode during the same 1 second running time.

> Speed: about 1~10/sec (without asan), 0.9/sec (with asan).
> Run time: more than two days
> Unique crashes: 0

To test your fuzzing methodology, can you please try applying it to JtR
1.7 release?  IIRC, I made the .chr file parser more robust between 1.7
and 1.7.0.1, so you should probably be able to trigger crashes on 1.7:

http://download.openwall.net/pub/projects/john/1.7/

You may see the history of changes around this time (early 2006) here:

http://cvsweb.openwall.com/cgi/cvsweb.cgi/Owl/packages/john/john/src/inc.c

There's no --max-run-time option in JtR 1.7 (and some other options
you're using are also missing), so you'll need to introduce another way
for terminating JtR - e.g., set CharCount low and use a fast hash type
(LM is the fastest supported in 1.7).

Thanks,

Alexander

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