Re: Certificate validation vulnerability in Git

Hello,

On Mon, Feb 25, 2013 at 12:16 AM, Andreas Ericsson [off-list ref] wrote:

On 02/24/2013 06:31 PM, Zubin Mithra wrote:

quoted

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

quoted

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Andreas Ericsson                   andreas.ericsson@op5.se
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