Once reconnaissance has been performed, exploitation must be performed for proof of concept. If the attack is being performed as part of a red team or wider assessment, then exploitation should be performed to gain access to the network as surreptitiously as possible.
In our attacking phase, we will explore the following:
- Cracking the encryption
- Attacking the infrastructure
- Compromising clients
- Finding vulnerable clients
- Finding unauthorized clients
The first step is to retrieve the keys for any vulnerable networks identified. If networks with WEP exist, perform the WEP-cracking methods explained in Chapter 4, WLAN Encryption Flaws. If WPA2-secured systems are present, you have two choices. If aiming to be stealthy, arrive on-site at times when individuals are likely to be authenticating or re-authenticating. These times are likely to be:
- Start of the day
- Lunch time
- End of the day
At this time, set up your WPA key retrieval setup as shown in Chapter 4, WLAN Encryption Flaws. Alternatively, perform the deauthentication attack, as shown in Chapter 6, Attacking the Client.
This is noisier and more likely to be detected in a mature organization.
If WPA-Enterprise is in place, bear in mind you will have to use the information gathered from the reconnaissance to target the correct network and set up your dummy Enterprise setup as shown in the Attacking PEAP section in Chapter 8, Attacking WPA-Enterprise and RADIUS.
You can attempt to break all passphrases but bear in mind that some will be unbreakable. Following the performance of the test, check with the wireless administrator for the passphrase in use. Check to see whether it is a secure passphrase and that you, as a tester, did not experience a tool failure or were merely unlucky.
If network access is gained through cracking the encryption, perform a standard network penetration test if allowed in scope. The following should be performed as a minimum:
- A port scan
- Identifying which services are running
- Enumerating any open services, such as unauthenticated FTP, SMB, or HTTP
- Exploiting any vulnerable services identified
After enumerating and testing all wireless systems, there are various types of engagements that would suit performing attacks against clients.
If necessary, after establishing which clients are vulnerable to Karma attacks, create a Honeypot to force them to connect with the methods laid out in the Attacking PEAP section in Chapter 8, Attacking WPA-Enterprise and RADIUS. There are various useful pieces of information that can be gathered through this method, but ensure that the collected data serves a purpose and is stored, transmitted, and used in an ethical and safe manner.