Actually, I think for most installations it is worse than your sentence "we believe it may severely impact those who have not already upgraded" may sound like. The problem is that even for installations that were upgraded immediately after the disclosure of the openssl bug we cannot be sure that private keys etc. might not have been stolen BEFORE the hole was publicly known. There are strong hints that knowledge of the problem was present long before last tuesday. So it probably means that any OpenVPN installation that was not protected by a TA key (or where the TA key is distributed to lots of users) needs to recreate the certificates used for the server and the clients.
Perhaps you or the openvpn developers can elaborate a bit on what can be found in the respective memory area; I understand you managed to get a private key or parts of it; what about password hashes used by plugins e.g.? Because this could mean that these passwords, which might be used in very different contexts if e.g. we talk about a PAM plugin, need to be changed too. And this would open attack vectors that are nor related to OpenVPN anymore. Regards, Jakob Curdes > Hi openvpn-users, > > We have successfully extracted private key material multiple times > from an OpenVPN server by exploiting the Heartbleed Bug. The material > we found was sufficient for us to recreate the private key and > impersonate the server. > > As you may know, OpenVPN has an SSL/TLS mode where certificates are > used for authentication. OpenVPN multiplexes the SSL/TLS session used > for authentication and key exchange with the actual encrypted tunnel > data stream. The default TLS library for OpenVPN is OpenSSL. Since > OpenVPN uses the OpenSSL library but merely passes through the TLS > traffic to OpenSSL, this means that OpenVPN is exploitable using > Heartbleed, in theory. However, until now there hasn't been any solid > evidence that private key material can be extracted from OpenVPN just > like it has from some web servers. > > This was the server setup we used: > Ubuntu 12.04 (VM using KVM) > OpenVPN 2.2.1 > OpenSSL 1.0.1-4ubuntu5.11 > > Our exploit is decently weaponized, and while the code is an > abomination that even Eris would be embarrassed to present, we believe > it may severely impact those who have not already upgraded. Therefore, > we will not be publishing the code. Nevertheless, you should assume > that other teams with more nefarious purposes have already created > weaponized exploits for OpenVPN. Just to be clear, we don't intend to > use this exploit ourselves. We merely developed it to examine the > practical impact on OpenVPN as part of our incident investigation. > > To our knowledge there is currently one published proof of concept > script that checks an OpenVPN server's vulnerability to Heartbleed. > > It should be noted that OpenVPN provides a feature called tls-auth > where a HMAC key is used to authenticate the packets that are > themselves part of the TLS handshake sequence. This protects against > Heartbleed to the extent that the HMAC key is kept secret. This means > that while a small business may benefit from using tls-auth because > only the employees have access to the key, a public VPN service such > as ours does not, because anyone who is a customer has access to the > key. > > Private questions that are not requests for the exploit can be emailed > to stromb...@insto.org or ad...@mullvad.net (PGP: 0x2C62E8AE). > > Best regards, > Fredrik Strömberg > Co-founder of Mullvad > > ------------------------------------------------------------------------------ > Learn Graph Databases - Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and their > applications. Written by three acclaimed leaders in the field, > this first edition is now available. Download your free book today! > http://p.sf.net/sfu/NeoTech > _______________________________________________ > Openvpn-users mailing list > Openvpn-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/openvpn-users ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. Written by three acclaimed leaders in the field, this first edition is now available. Download your free book today! http://p.sf.net/sfu/NeoTech _______________________________________________ Openvpn-users mailing list Openvpn-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openvpn-users
