diff options
Diffstat (limited to 'users/tazjin/blog/posts')
| -rw-r--r-- | users/tazjin/blog/posts/reversing-watchguard-vpn.md | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/users/tazjin/blog/posts/reversing-watchguard-vpn.md b/users/tazjin/blog/posts/reversing-watchguard-vpn.md index f1b779d8d993..8968dc864590 100644 --- a/users/tazjin/blog/posts/reversing-watchguard-vpn.md +++ b/users/tazjin/blog/posts/reversing-watchguard-vpn.md @@ -5,7 +5,7 @@ doing that first before reading the response to have the proper context. ------------------------------------------------------------------------ -One of my current client makes use of +One of my current clients makes use of [WatchGuard](http://www.watchguard.com/help/docs/fireware/11/en-US/Content/en-US/mvpn/ssl/mvpn_ssl_client-install_c.html) Mobile VPN software to provide access to the internal network. @@ -15,22 +15,22 @@ provided, but it quickly turned out that this was only a piece of the puzzle. The problem is that this VPN setup is secured using 2-factor -authentication (good!), but it does not use OpenVPN\'s default +authentication (good!), but it does not use OpenVPN's default [challenge/response](https://openvpn.net/index.php/open-source/documentation/miscellaneous/79-management-interface.html) functionality to negotiate the credentials. Connecting with the OpenVPN config that the website supplied caused the -VPN server to send me a token to my phone, but I simply couldn\'t figure +VPN server to send me a token to my phone, but I simply couldn't figure out how to supply it back to the server. In a normal challenge/response setting the token would be supplied as the password on the second authentication round, but the VPN server kept rejecting that. Other possibilities were various combinations of username&password -(I\'ve seen a lot of those around) so I tried a whole bunch, for example +(I've seen a lot of those around) so I tried a whole bunch, for example `$password:$token` or even a `sha1(password, token)` - to no avail. At this point it was time to crank out -[Hopper](https://www.hopperapp.com/) and see what\'s actually going on +[Hopper](https://www.hopperapp.com/) and see what's actually going on in the official OS X client - which uses OpenVPN under the hood! Diving into the client @@ -95,7 +95,7 @@ formatted the URL, opened it and checked whether the `logon_status` was `4` before proceeding with the `logon_id` and `chaStr` contained in the response. -*(Code snippets from here on are Hopper\'s pseudo-Objective-C)* +*(Code snippets from here on are Hopper's pseudo-Objective-C)*  @@ -112,7 +112,7 @@ to do something quite interesting:  -The user\'s password was overwritten with the (verified) OTP token - +The user's password was overwritten with the (verified) OTP token - before OpenVPN had even been started! Reading a bit more of the code in the subsequent @@ -130,29 +130,29 @@ after configuring OpenVPN with the correct config file: TL;DR ----- -Rather than using OpenVPN\'s built-in challenge/response mechanism, the +Rather than using OpenVPN's built-in challenge/response mechanism, the WatchGuard client validates user credentials *outside* of the VPN connection protocol and then passes on the OTP token, which seems to be -temporarily in a \'blessed\' state after verification, as the user\'s +temporarily in a 'blessed' state after verification, as the user's password. -I didn\'t check to see how much verification of this token is performed +I didn't check to see how much verification of this token is performed (does it check the source IP against the IP that performed the challenge validation?), but this certainly seems like a bit of a security issue - considering that an attacker on the same network would, if they time the attack right, only need your username and 6-digit OTP token to authenticate. -Don\'t roll your own security, folks! +Don't roll your own security, folks! Bonus ----- The whole reason why I set out to do this is so I could connect to this -VPN from Linux, so this blog post wouldn\'t be complete without a +VPN from Linux, so this blog post wouldn't be complete without a solution for that. -To make this process really easy I\'ve written a [little +To make this process really easy I've written a [little tool](https://github.com/tazjin/watchblob) that performs the steps mentioned above from the CLI and lets users know when they can authenticate using their OTP token. |