Rogue-Ap
PEAP Relay Attacks with wpa_sycophant
Back in 2018, I was interested that MSCHAPv2 and NTLMv1 hashes crack using the same algorithms, and wanting to get onto the WiFi of one of our clients, I naively thought “Surely if you can relay NTLMv1 and it uses the same crypto as MSCHAPv2, you should be able to relay MSCHAPv2!”. The resulted in the creation of wpa_sycophant (and its helper berate_ap) to perform PEAP relay attacks. It was presented in our Defcon talk last year from about 17m in.
Understanding PEAP In-Depth
tl;dr
We reported a long standing PEAP bug in all Apple devices that would allow an attacker to force any Apple device (iOS, macOS or tvOS) to associate with a malicious access point, even if the authentication server (RADIUS) couldn’t prove knowledge of the password. To understand it fully, we go on a deep dive into EAP and MSCHAPv2.
Table of Contents PEAP at a High LevelMSCHAPv2Decrypting the Inner TunnelThe Inner MSCHAPv2 ExchangeByte-Level Description of the MSCHAPv2 ExchangeMSCHAPv2 CalculationsMSCHAPv2 Failure BehaviourThe Apple VulnerabilityApple’s FixDisclosure Timeline & DetailsOriginal Vulnerability Report While prepping for our Defcon talk last year, Michael kept pushing me to implement hostapd-wpe‘s EAP success attack. In this attack, the authentication server will accept any username, then skip the step where it proves knowledge of the password back to the station (because it doesn’t know the password), and instead sends an EAP-success message back to the station. I refused for a long time, because I thought it was a dumb attack that would never work. This is because in MSCHAPv2 the authentication server also proves knowledge of the password back to the station, and if it couldn’t, I assumed the station would just refuse to continue, after all, that’s the whole point.
Handling Randomised MAC Addresses in MANA
mana development has been chugging along nicely. However, the OffSec crew politely asked us to move mana to proper releases a while back, which we’ve just done. This is about one of the many changes pushed in our first new set of releases since October 2014; 1.3.1-Fixy McFixface. There’s a longer summary of what’s new available at the previous release page 1.3-WPE & ACLs with the WPE functionality extensions from and inspired by Brad Antoniewicz’s work being the coolest from a pwnage perspective.
Too Easy – Adding Root CA’s to iOS Devices
With the recent buzz around the iMessage crypto bug from the John’s Hopkins team, several people pointed out that you would need a root CA to make it work. While getting access to the private key for a global root CA is probably hard, getting a device to trust a malicious root CA is sometimes phrased as difficult to do, but really isn’t. (There’s a brief technical note about this in the caveats section at the end.)
Improvements in Rogue AP attacks – MANA 1/2
At Defcon 22 we presented several improvements in wifi rogue access point attacks. We entitled the talk “Manna from heaven” and released the MANA toolkit. I’ll be doing two blog entries. The first will describe the improvements made at a wifi layer, and the second will cover the network credential interception stuff. If you just want the goodies, you can get them at the end of this entry for the price of scrolling down.
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