![]() ![]() The reason why two access-accept packets are extracted during the capture is that the session timeout timer is set to 30 mins on this particular SSID and the capture is 34 mins long. Run the radsniff against radius capture between NAS and Authenticator in order to extract PMK. Decrypt PMK(s) from Access-accept Packet. In this example, two Pairwise Master Keys (PMKs) are derived from Radius packets captured from ISE 2.3, as the session timeout on this SSID is 1800 secs, and the capture given here is 34 mins (2040 secs) long.Īs shown in the image, EAP-PEAP is used as an example, but this can be applied to any dot1x based wireless authentication. If your network is live, ensure that you understand the potential impact of any command. All of the devices used in this document started with a cleared (default) configuration. The information in this document was created from the devices in a specific lab environment. The information in this document is based on these software and hardware versions: Ability to perform Over-the-Air (OTA) capture containing four-way EAPoL handshakes.Ability to capture radius packet capture between NAS and authenticator from the first access-request (from NAS to Authenticator) to the last access-accept (from Authenticator to NAS) throughout the EAP session.Privilege to obtain the shared secret between network access server (NAS ) and Authenticator.Wireshark/Omnipeek or any software that is capable of decrypting 802.11 wireless traffic.Prerequisites RequirementsĬisco recommends that you have knowledge of these topics: Hence, many enterprises choose dot1x with Remote Authentication Dial-In User Service (RADIUS ) as a better security solution for their wireless network. Cracking a hard-coded password is just a matter of time. However, Pre-shared Key (PSK) is not always recommended from a security perspective. ![]() It is relatively easy to decrypt PSK based/WPA2-personal 802.11 OTA capture as long as the full four-way EAP over LAN (EAPoL) handshakes are captured. I don't think this matches the OP case - there, server ends the connection in TLS-appropriate way, with Encrypted Alert - but nevertheless, something to consider for anyone hitting this page.This document describes a how-to of decrypting Wi-Fi Protected Access 2 - Enterprise (WPA2-Enterprise) or 802.1x (dot1x) encrypted wireless over-the-air (OTA) sniffer, with any Extensible Authentication Protocol (EAP) methods. One more reason to say its a server bug in my case - the behavior stopped reproducing as soon as we swapped out the ftps server for a different implementation, proftpd. pure-ftpd uses apache-like fork-per-connection model and I observed the child process crashing in gdb (exiting with code -1) - which of course leads to the OS closing the socket FD and sending FIN. I haven't dig up the root of the issue, but I suspect we hit a server bug. This happened only with one single specific client (a device firmware), and didn't reproduce with other ftps clients. Next, the client sent the Encrypted alert, level 1 code 0 Close Notify (which is expected - unlike the server FIN). In my case though, there was no Encrypted Alert sent from server it just Fin'd immediately after key exchange ( Change Cipher Spec, Finished message from server → FIN from server). I've run into a similar issue with pure-ftpd in explicit TLS mode (FTPS server). ![]()
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