4
Encryption/Privacy/Authentication Project Report
Wireless Networks
Chris H, Chris R, Mindy C
04/27/07
Table of Contents
1 Overview 4
2 Procedure 4
2.1 Packet Capture 4
2.1.1 Overview 4
2.1.2 Procedure 4
2.2 Encryption Cracking 6
2.2.1 Overview 6
2.2.2 Procedure 6
3 Results 8
3.1 Packet Capture 8
3.1.1 Overview 8
3.1.2 Data 8
3.2 Encryption Cracking 14
3.2.1 Overview 14
3.2.2 Data 15
4 Summary and Conclusions 19
Table of Figures
Figure 1 - WEP64 Authentication 9
Figure 2 - WEP128 Authentication 9
Figure 3 – WPA Personal TKIP Authentication 9
Figure 4 - WPA Personal AES Authentication 9
Figure 5 - WPA2 Personal TKIP/AES Authentication 10
Figure 6: Kismet Capturing Traffic 15
Figure 7: Encrypted Traffic 15
Figure 8: Network Selection 16
Figure 9: Key Found 16
Figure 10: Failed crack attempt 17
Figure 11: Airodump-ng capturing WEP traffic 17
Figure 12: Airodump-ng capturing WPA traffic 17
Figure 13: Aireplay-ng attempting to generate a handshake 18
Figure 14: WPA Handshake Confirmation 18
Figure 15: WPA Key Found 18
Figure 16: WPA2 Key Found 19
1 Overview
Our goal was to evaluate the relative security between WEP 64-bit, WEP 128-bit, WPA, and WPA2. The methods of evaluation were broken into two main efforts, cracking & evaluation/setup of each system. Our encryption attacking efforts consisted of using a range of tools to breach the security of each wireless protection scheme. The results of our attempts have been recorded in this report. The other piece of our evaluation consisted of setting up each security protocol, capturing traces, and comparing data/communication.
2 Procedure
2.1 Packet Capture
2.1.1 Overview
The setup for these sets of experiments was accomplished in the ITL Wireless Evaluation Network (ITL-WEN). The setup consisted of a Linksys N Access Point connected to a server. The server acted as a host for two other machines with wireless network cards. One of the clients was setup to connect, download, and generate traffic for the other machine to capture traffic via Wireshark. Below we have listed the steps taken to setup each protocol, connect to the access point, generate traffic, and trace the traffic.
2.1.2 Procedure
1) Wired Equivalent Privacy (WEP)
A) WEP – 64 bit encryption (wep64.pcap)
1. Set the security on the Linksys to WEP, with 64 bit encryption.
2. Passphrase set to: goknights
3. After clicking “generate” 4 keys were created.
4. Save configuration.
5. On tracing machine, start trace.
6. On ITL-Wireless-1, connect to the test network by typing one of the keys.
7. Connect to: 192.168.1.102/files.
8. Begin downloading file FC-6-1386-disc1.iso
9. After about a minute of downloading, cancel the download.
10. Disconnect ITL-Wireless-1 from the test network.
11. On tracing machine: stop trace, save file.
B) WEP-128 bit encryption (wep128.pcap)
1. Set the security on the Linksys to WEP, with 128 bit encryption.
2. Passphrase set to: goknights
3. After clicking “generate” 4 keys were created.
Example of 128 bit key:7A08BC60865F25EA684F4801FA (Yikes!)
4. Save configuration.
5. On tracing machine, start trace.
6. On ITL-Wireless-1, connect to the test network by typing one of the keys.
7. Connect to: 192.168.1.102/files.
8. Begin downloading file FC-6-1386-disc1.iso
9. After about a minute of downloading, cancel the download.
10. Disconnect ITL-Wireless-1 from the test network.
11. On tracing machine: stop trace, save file.
2) WiFi Protected Access (WPA) Personal
A) WPA – TKIP encryption (wpa-Personal-TKIP.pcap)
1. Set the security on the Linksys to WPA Personal, with TKIP encryption.
2. Pre-shared key: 7A85B6E2
3. Save configuration.
4. On tracing machine, start trace.
5. On ITL-Wireless-1, connect to the test network by typing in the pre-shared key.
6. Connect to: 192.168.1.102/files.
7. Begin downloading file FC-6-1386-disc1.iso
8. After about a minute of downloading, cancel the download.
9. Disconnect ITL-Wireless-1 from the test network.
10. On tracing machine: stop trace, save file.
B) WPA – AES encryption (wpa-Personal-AES.pcap)
1. Set the security on the Linksys to WPA Personal, with AES encryption.
2. Pre-shared key: 7A85B6E2
3. Save configuration.
4. On tracing machine, start trace.
5. On ITL-Wireless-1, connect to the test network by typing in the pre-shared key.
6. Connect to: 192.168.1.102/files.
7. Begin downloading file FC-6-1386-disc1.iso
8. After about a minute of downloading, cancel the download.
9. Disconnect ITL-Wireless-1 from the test network.
10. On tracing machine: stop trace, save file.
3) WiFi Protected Access 2 (WPA2) Personal
A) WPA2 – AES encryption
1. Set the security on the Linksys to WPA2 Personal, with AES encryption.
2. Pre-shared key: 7A85B6E2, 7A85B6A7 (tried twice)
3. Save configuration.
4. On tracing machine, tried connecting with two different pre-shared keys. Unable to connect.
B) WPA2 – TKIP or AES encryption (wpa2-Personal-(TKIP-AES).pcap)
1. Set the security on the Linksys to WPA2 Personal, with TKIP or AES encryption.
2. Pre-shared key: 7A85B6A7
4. Save configuration.
5. On tracing machine, start trace.
6. On ITL-Wireless-1, connect to the test network by typing in the pre-shared key.
7. Connect to: 192.168.1.102/files.
8. Begin downloading file FC-6-1386-disc1.iso
9. After about a minute of downloading, cancel the download.
10. Disconnect ITL-Wireless-1 from the test network.
11. On tracing machine: stop trace, save file.
4) Security Disabled (noSecurity.pcap)
1. Set the security on the Linksys to Security Disabled.
2. Save configuration.
3. On tracing machine, connect to the test network. *The message when connecting says, connection established, however on the networks interface, it says not connected to the network.
4. Connect to: 192.168.1.102/files.
5. Begin downloading file FC-6-1386-disc1.iso
6. After about a minute of downloading, cancel the download.
7. Disconnect ITL-Wireless-1 from the test network.
8. On tracing machine: stop trace, save file.
2.2 Encryption Cracking
2.2.1 Overview
The setup for the encryption cracking portion of our project was accomplished in a private residence away from Clarkson University’s wireless network. A Linksys WRT-54G wireless router was configured as solely an access point. It served as the main connection to the Internet. This access point was running dd-wrt firmware, which allows access to advanced options for the router. Two laptops were used to generate traffic one running Windows 2000 and another running Mac OSX. The third laptop running Ubuntu was used to capture traffic as well as was used to crack the three encryptions WEP, WPA, WPA2. The program airodump-ng was used to capture the initialization vectors and handshakes from the different encryption. Aircrack-ng was used to break each encyption was enough packets were captured.
2.2.2 Procedure
1) Wired Equivalent Privacy (WEP)
A) WEP – 64 bit encryption
1. Set the security on the Linksys to WEP, with 64 bit encryption.
2. Renamed router to test.
3. Save settings.
4. Passphrase set to: test
5. After clicking “generate” 4 keys were created.
6. Save settings.
7. On tracing machine, start trace to capture on channel 6.
Command: airodump-ng --ivs –c 6 eth1
8. Connect to: test network (10.0.0.2).
9. Connect to: http://www.hp.com
10. Begin downloading large driver files > 200 MB each
11. Watch airodump-ng till about 500,000 initialization vectors.
12. Stop trace on tracing machine, stop airodump-ng.
13. Start aircrack-ng to begin cracking WEP
Command: aircrack –ng –a 1 –n 64 WEP-64-Capture.dump
14. Wait for one of two outcomes from aircrack-ng
1. Key Found [network key contained here]
2. Try capturing more packets and try again.
B) WEP – 128 bit encryption
1. Set the security on the Linksys to WEP, with 128 bit encryption.
2. Renamed router to test.
3. Save settings.
4. Passphrase set to: test
5. After clicking “generate” 4 keys were created.
6. Save settings.
7. On tracing machine, start trace to capture on channel 6.
Command: airodump-ng --ivs –c 6 eth1
8. Connect to: test network (10.0.0.2).
9. Connect to: http://www.hp.com
10. Begin downloading large driver files > 200 MB each
11. Watch airodump-ng till about 1.5 million initialization vectors.
12. Stop trace on tracing machine, stop airodump-ng.
13. Start aircrack-ng to begin cracking WEP
Command: aircrack –ng –a 1 –n 128 wep128_cap-01.ivs
14. Wait for one of two outcomes from aircrack-ng
1. Key Found [network key contained here]
2. Try capturing more packets and try again.
2) Wi-Fi Protected Access (WPA, WPA2)
A) WPA
1. Set the security on the Linksys to WPA with TKIP.
2. Renamed router to test.
3. Save settings.
4. Passphrase set to: engineering
5. After clicking “generate” 4 keys were created.
6. Save settings.
7. On tracing machine, start trace to capture on channel 6.
Command: airodump-ng –c 6 eth1
8. Connect to: test network (10.0.0.2).
9. Disconnect laptop running Mac OS X
11. Reconnect laptop to generate a WPA handshake.
12. Stop trace on tracing machine, stop airodump-ng.
13. Start aircrack-ng to begin cracking WPA
Command: aircrack –ng –w length11.txt WPA-09.cap
14. Choose network that needs to be cracked: 1, 2, … etc.
14. Wait for one of two outcomes from aircrack-ng
1. Key Found [network key contained here]
2. Key Not Found.
B) WPA2
1. Set the security on the Linksys to WPA2 with TKIP.
2. Renamed router to test.
3. Save settings.
4. Passphrase set to: construction
5. After clicking “generate” 4 keys were created.
6. Save settings.
7. On tracing machine, start trace to capture on channel 6.
Command: airodump-ng –c 6 eth1
8. Connect to: test network (10.0.0.2).
9. Disconnect laptop running Mac OS X
11. Reconnect laptop to generate a WPA handshake.
12. Stop trace on tracing machine, stop airodump-ng.
13. Start aircrack-ng to begin cracking WPA
Command: aircrack –ng –w length12.txt WPA2-02.cap
14. Choose network that needs to be cracked: 1, 2, … etc.
14. Wait for one of two outcomes from aircrack-ng
1. Key Found [network key contained here]
2. Key Not Found.
3 Results
3.1 Packet Capture
3.1.1 Overview
Our capturing efforts resulting in six different capture files:
· noSecurity.pcap
· wep64.pcap
· wep128.pcap
· wpa-Personal-AES.pcap
· wpa-Personal-TKIP.pcap
· wpa2-Personal-(TKIP-AES).pcap
We made sure that we filtered out traffic from other network devices so that we were ONLY evaluating traffic on the ITL-WEN. Using a range of filters we evaluated the different capture files and did comparisons between each capture file.
3.1.2 Data
To make sure that we were only evaluating traffic between the ITL-WEN we applied a filter to the MAC addresses of every packet:
wlan.bssid == 00:18:f8:c5:5d:3e
After we applied this filter we also used a few other filters to look more closely at particular packets. To filter out beacon frames we applied the following filter:
(wlan.fc.type_subtype != 8)
Filtering of probe frames was accomplished via the below filter:
(wlan.fc.type_subtype != 5) & (wlan.fc.type_subtype != 4)
Finally to just look at the authentication frames we applied the following expression:
(llc.type == 0x888e) || (wlan.fc.type_subtype == 11) || (wlan.fc.type_subtype == 0) || (wlan.fc.type_subtype == 1) || (wlan.fc.type_subtype == 12)
3.1.2.1 Authentication
This filter also allowed us to observe the key being passed to the server. Figure 1 through 5 show the results of filtering out everything but the authentication process. There are some simple observations that can be made from just comparing each authentication process. The authentication process involves the station sending some authentication frames. Then the station must associate with the AP by sending an Association Request. The AP grants access by returning with an Association Response.
WEP64 and WEP128 appear very similar in their authentication process. The authentication time is hardly different between the two protocols. There is a much more noticeable difference between WEP and WPA. The biggest difference is the presence of KEY frames. The process of transferring a key appears to take about a second on a B/G Mixed network.
WEP64 Authentication
Figure 1 - WEP64 Authentication
WEP128 Authentication
Figure 2 - WEP128 Authentication
WPA Personal TKIP Authentication
Figure 3 – WPA Personal TKIP Authentication
WPA Personal AES Authentication
Figure 4 - WPA Personal AES Authentication
WPA2 Personal TKIP/AES Authentication
Figure 5 - WPA2 Personal TKIP/AES Authentication
Security / Authentication Time (Seconds)WEP64 / .0047
WEP128 / .0049
WPA Personal TKIP / 1.013
WPA Personal AES / 1.012
WPA2 TKIP/AES / 1.013
The table above summarizes the length of time, in seconds, it takes to complete the authentication periods for each of the security schemes tested. Although the time difference seems minimal, less than a second, WPA’s authentication period is at least 200 times that of WEP.
3.1.2.2 WPA’s Encryption
There are two types of encryption options for WPA Pre-Shared Key, both of which were tested in this exercise, TKIP and AES. Temporal Key Integrity Protocol (TKIP) uses a stronger encryption method and incorporates Message Integrity Code (MIC), shown in figure 6, providing protection against hackers. This MIC enables devices to authenticate that the packets are coming from the claimed source. This authentication is important since in wireless technology traffic can be easily injected.
Since WPA was created to correct deficiencies in the older WEP standard, it was important that TKIP work on the legacy hardware. For this reason, TKIP, like WEP, use a key scheme based on RC4. However, unlike WEP, TKIP ensures that every data packet is sent with its own unique encryption key with per-packet key mixing. TKIP’s encryption keys are also stronger, since they are 256 bits long.
While WEP generates the key using the shared secret key and the IV (Initialization Vector) as an input, TKIP adds the transmitter’s MAC address to the list of the input parameters which implies that all senders will have different encryption keys. Furthermore, TKIP increases the size of the IV from 24-bit (used by WEP) to 48-bit and mandates that it is used as a counter (also called TSC – TKIP Sequence Counter), which guarantees that it will only be reused once for every 281,474,976,710,656 (248) packets.