Re: Certificate validation vulnerability in Git

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Hello,

On Mon, Feb 25, 2013 at 12:16 AM, Andreas Ericsson <ae@xxxxxx> wrote:
> On 02/24/2013 06:31 PM, Zubin Mithra wrote:
>> Hello,
>>
>> There seems to be a security issue in the way git uses openssl for
>> certificate validation. Similar occurrences have been found and
>> documented in other open source projects, the research can be found at
>> [1].
>>
>> -=========]
>> - imap-send.c
>>
>> Line 307
>>
>>   307   ret = SSL_connect(sock->ssl);
>>   308   if (ret <= 0) {
>>   309     socket_perror("SSL_connect", sock, ret);
>>   310     return -1;
>>   311   }
>>   312
>>
>> Certificate validation errors are signaled either through return
>> values of SSL_connect or by setting internal flags. The internal flags
>> need to be checked using the SSL_get_verify_result function. This is
>> not performed.
>>
>> Kindly fix these issues, file a CVE and credit it to Dhanesh K. and
>> Zubin Mithra. Thanks.
>>
>
> The lack of certificate authority verification presents no attack vector
> for git imap-send. As such, it doesn't warrant a CVE. I'm sure you'll
> be credited with a "reported-by" line in the commit message if someone
> decides to fix it though. Personally, I'm not fussed.

I'd like to add in a few points -- generally SSL/TLS would be used in
cases where the authenticity of the server and confidentiality of the
messages transferred would be required. In this particular case, the
threat scenarios would be :-

- Usage of an invalid attacker certificate could result in the
attacker gaining access to authentication information sent over the
wire.
- If the code repository were private, the patches thus generated are
also assumed to be kept private. An invalid certificate check at the
client side would enable an attacker to gain access to those patches.


Is there anything I'm missing? I believe this is a valid security issue.



Thanks,
Zubin


>
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>
> --
> Andreas Ericsson                   andreas.ericsson@xxxxxx
> OP5 AB                             www.op5.se
> Tel: +46 8-230225                  Fax: +46 8-230231
>
> Considering the successes of the wars on alcohol, poverty, drugs and
> terror, I think we should give some serious thought to declaring war
> on peace.
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