[guardian-dev] Smack SSL MiTM Vuln and ChatSecure beta fix

[Nathan of Guardian]

On 08/05/2014 06:18 PM, Tom Ritter wrote:
> I didn't see any mention of the security fix in the blog post, but it
> is in the referenced APK?  Do you know when this bug was introduced or
> which versions of ChatSecure were vulnerable?

I wrote the blog post before the vulnerability was public, so I need to
update it now with more details. The fix is definitely included as part
of the 13.2.0-beta-1 tagged release.

As for as when the vulnerability was introduced, the vuln info page is
pretty clear about when it was introduced into Smack itself. However,
with ChatSecure, I am still sorting out the timeline and just trying to
determine how exposed we really are.

In fact, since we use a custom SSLContext, and only rely on
PinningTrustManger and MemorizingTrustManager, I think we may actually
not be as vulnerable as I thought:

https://github.com/guardianproject/ChatSecureAndroid/blob/master/src/info/guardianproject/otr/app/im/plugin/xmpp/XmppConnection.java#L1139

sslContext = SSLContext.getInstance(SSLCONTEXT_TYPE);

                mTrustManager = getTrustManager ();

                SecureRandom mSecureRandom = new
java.security.SecureRandom();

                sslContext.init(null, new javax.net.ssl.TrustManager[] {
mTrustManager },
                        mSecureRandom);


sslContext.getDefaultSSLParameters().setCipherSuites(XMPPCertPins.SSL_IDEAL_CIPHER_SUITES);

https://github.com/guardianproject/ChatSecureAndroid/blob/master/src/info/guardianproject/otr/app/im/plugin/xmpp/XmppConnection.java#L1415

public synchronized X509TrustManager getTrustManager ()
    {
        if (mTrustManager == null)
        {
            PinningTrustManager trustPinning = new
PinningTrustManager(SystemKeyStore.getInstance(aContext),XMPPCertPins.getPinList(),
0);

            mTrustManager = new MemorizingTrustManager(aContext,
trustPinning);


        }

        return mTrustManager;
    }


> -tom
> 
> On 5 August 2014 15:59, Nathan of Guardian <nathan at guardianproject.info> wrote:
>>
>> Thanks to Georg of Yaxim for his great work on this, both technically
>> and in coordinating with us.
>>
>> https://op-co.de/CVE-2014-5075.html
>>
>> "Smack is an Open Source XMPP (Jabber) client library for instant
>> messaging and presence written in Java. Smack prior to version 4.0.2 is
>> vulnerable to TLS Man-in-the-Middle attacks, as it fails to check if the
>> server certificate matches the hostname of the connection."
>>
>> https://op-co.de/blog/posts/java_sslsocket_mitm/
>>
>> Our fix for ChatSecure:Android
>> (https://github.com/guardianproject/ChatSecureAndroid/commit/3f150daded7461255b9d51bfc59ff91f8a77ed81)
>> is included in the new ChatSecure 13.2.0 beta out today, which is near
>> enough to stable, that we recommend an upgrade:
>>
>> https://guardianproject.info/2014/08/05/chatsecure-13-2-important-beta-update/
>>
>> +n
>>
>>
>>
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