oss-security - Re: CVE Request -- mcrypt: stack-based buffer overflow by encryption / decryption of overly long file names

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Date: Mon, 19 Nov 2012 22:12:04 -0500 (EST)
From: "Steven M. Christey" <coley@...-smtp.mitre.org>
To: oss-security@...ts.openwall.com
cc: Jan Lieskovsky <jlieskov@...hat.com>,
        "Steven M. Christey" <coley@...-smtp.mitre.org>,
        Attila Bogar <attila.bogar@...guamatics.com>,
        Raphael Geissert <geissert@...ian.org>
Subject: Re: CVE Request -- mcrypt: stack-based buffer overflow
 by encryption / decryption of overly long file names


For my own clarification - where does this long file name come from?  If 
it's only provided on the command line, then I don't see how this would be 
a vulnerability, since the person executing mcrypt would only be attacking 
themselves.  (CVE-2012-4409 is still OK since one wouldn't expect code 
execution when decrypting the contents of a file.)

Thanks,
Steve


On Thu, 18 Oct 2012, Kurt Seifried wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
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> On 10/18/2012 07:50 AM, Jan Lieskovsky wrote:
>> Hello Kurt, Steve, vendors,
>>
>>   Attila Bogar reported a stack-based buffer overflow
>> in the way MCrypt, a crypt() package and crypt(1) command
>> replacement, used to encrypt / decrypt files with overly
>> long names (longer than 128 bytes). A remote attacker
>> could provide a specially-crafted file that, when processed
>> by the mcrypt too, would lead to mcrypt executable crash [*].
>>
>> A different vulnerability than CVE-2012-4409:
>> [1] https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2012-4409
>>
>> Note: Using Red Hat bugzilla record for CVE-2012-4409 since
>> particular Mitre record is not described yet.
>>
>> References:
>> [2] https://bugzilla.redhat.com/show_bug.cgi?id=867790
>>
>> Patch proposed by Attila:
>> [3] https://bugzilla.redhat.com/show_bug.cgi?id=867790#c0
>>
>> Reproducer:
>> To reproduce let mcrypt encrypt / decrypt file with name
>> longer ~128 bytes.
>>
>> Could you allocate a CVE id for this?
>>
>> Thank you && Regards, Jan.
>> --
>> Jan iankko Lieskovsky / Red Hat Security Response Team
>>
>> [*] FORTIFY_SOURCE protection mechanism would mitigate this
>> deficiency to result into crash only. But on systems, without
>> FORTIFY_SOURCE protection being applied, the impact might be
>> higher.
>>
>> P.S.: I am not sure about relation of this issue to the issue
>>       Raphael Geissert reported previously:
>>       [4] http://www.openwall.com/lists/oss-security/2012/10/02/1
>>
>>       so CC-in him too, he to clarify if [2] == [4], or if
>>       they are yet different issues. Raphael, please clarify.
>>       Thanks, Jan.
>>
>
> Please use CVE-2012-4527 for this issue.
>
> - --
> Kurt Seifried Red Hat Security Response Team (SRT)
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