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Date: Thu, 13 Aug 2015 19:50:30 +0200
From: magnum <john.magnum@...hmail.com>
To: john-dev@...ts.openwall.com
Subject: episerver UTF-8 (was: Re: Lei's weekly report #15)
On 2015-08-13 12:17, Lei Zhang wrote:
> On Aug 13, 2015, at 5:26 AM, magnum <john.magnum@...hmail.com> wrote:
>>
>> Maybe you could even add episerver to pass_gen.pl?
>
> I'm not sure what you mean. I can see episerver is already in pass_gen.pl.
>
> I don't know if I'm doing it correctly, but that's how I did the test:
>
> $ cat pw-utf8.dic | ../run/pass_gen.pl -utf8 episerver_sha1 > tst_utf8.in
> $ ../run/john --format=episerver --wordlist=pw-utf8.dic tst_utf8.in --encoding=utf8
Ah, I just tried "pass_gen.pl episerver". Good, then it's easy to create
more test vectors.
> And there're 257 out of 1500 hashes not cracked. I viewed the corresponding uncracked passwords: most of them are long (probably exceed PLAINTEXT_LENGTH), but some are not. For example, '€€€€€€€' cannot be cracked, while '€€€€€€' (one less char) can be cracked. The length of it surely doesn't exceed PLAINTEXT_LENGTH. Is there something special with this string? I feel I'm still missing some point in the UTF8 encoding...
Each '€' results in three bytes of UTF-8. '€€€€€€€' is thus 21 bytes,
and exceeds PLAINTEXT_LENGTH (which is given in bytes) while '€€€€€€' is
18 bytes and fits within it. So from the sound of it, your format is AOK.
BTW that's the reason for this, found in all FMT_UTF8 formats:
if (pers_opts.target_enc == UTF_8)
self->params.plaintext_length = MIN(125, 3 * PLAINTEXT_LENGTH);
This allows up to 57 bytes of key for up to 19 characters of UTF-8. And
while Jumbo formats otherwise never need to truncate/check max length,
UTF-8 formats has to do that, after the above. Because the added room
for 57 bytes would also allow a plain ASCII key of up to 57 characters -
which we can't allow writing past buffer!
magnum
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