*** This bug is a security vulnerability ***

Public security bug reported:

Recently, we are trying to find SSL security problems by static
analysis. For example, as we all know, Hostname verification is an
important step when verifying X509 certificates, however, people tend to
miss the step or to misunderstand the APIs when using SSL/TLS, which
might cause severe man in the middle attack and break the entire TLS
mechanism. And static analysis is a way of finding whether the APIs are
called correctly.

Now, we find some SSL problems in links:
1. miss hostname check when verify x509 certificate
2. miss expired time check when verify x509 certificate

More specifically , we can take function SSL_CTX_set_verify() for
example, when using OPENSSL, if we call SSL_CTX_set_verify(ssl_ctx,
SSL_VERIFY_NONE, null), we should verify the certificate by calling the
function SSL_get_peer_certificate() to get the certificate at first.
Then use X509 APIs or self-define function to verify the certificate we
get. If the source code does not match this model, then we can deduce
this code is vulnerable. And other APIs have similar problems.

To verify the result we make, we prove the vulnerability manually.
Result :we can browse any website with invalid certificate and we won’t get any 
warnings. 

PS:
for more information, you can see the paper: 
http://people.stfx.ca/x2011/x2011ucj/SSL/p38-georgiev.pdf
and more details you can contact with us, we will be very glad for your 
responce.

Thanks.

** Affects: links2 (Ubuntu)
     Importance: Undecided
         Status: New

** Information type changed from Private Security to Public Security

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https://bugs.launchpad.net/bugs/1381936

Title:
  SSL connection is not secure in links

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