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PROJECT TAKE MY DEVICE BUT NOT MY DATA DATE AUGUST 12, 2008 CLIENT TASSCC 2008 ANNUAL CONFERENCE Monday, August 18, 2008 1 Good Morning - I’m glad to be here at TASSCC, to be back in Galveston, and to have the opportunity to speak to you today about mobile devices, and security of the data on these devices that are so predominantly in use in today’s work environment. Goal To provide an overview about risks associated with the use of mobile devices especially in a wireless world Monday, August 18, 2008 2 My basic goal with today’s presentation to highlight some of the risks that come with the use of mobile devices , for example just recently CNN ran a story about drive by wireless hacking which some of you may have seen. The story is just one illustration of how even today, given the fact that wireless networks have been around for awhile there still are it seems plenty of available wireless networks that are not adequately secured or even secured at all Discussion Areas Physical Security Mobile Devices Public Wireless Enterprise Monday, August 18, 2008 3 Discussion areas that I will be discussing will include physical security, which perhaps is somewhat overlooked as an important component of technical security in general, but certainly for mobile devices and the security of your data. Since the title of the presentation includes the words mobile device, I guess we’ll also discuss mobile devices... Public wireless - personal computer use sure but also with a focus on the use of public wireless with a work computer, The easiest way for someone to be able to take their time trying to read the data on your mobile device is to take it from you permanently. Therefore, road warriors must always keep in mind the physical security aspect of security Enterprise - policies in the enterprise, authorized mobile devices managed appropriately, are wireless projects properly authorized, and managed in operation Contents Home Networks Tools Monday, August 18, 2008 4 I’m going to touch on home networks because Go over some of the tools we use with our audits and security service consulting Threats Rogue Access Point Misconfigured Access Point Client Mis-association WEP - dinosaur or still breathing? Monday, August 18, 2008 5 The most common, as well as most dangerous, wireless threat is the rogue access point. The rogue access point is typically a low cost, SOHO-class access point brought in by an employee who desires wireless access. The default access point settings typically have no security enabled, and thus when plugged into the corporate network create an entry-point for anyone with a Wi-Fi client within range For those enterprises with a wireless LAN infrastructure, one potential threat can arise from their own equipment. An access point which becomes mis-configured can potentially open up a door to the corporate network. In particular, if the access point is reset to network defaults or the security settings are turned off. If the access point is not centrally managed, then the likelihood of it going unnoticed is high. Employees will still be able to connect so no problem will be reported. Embedded Wi-Fi clients in laptops are now relatively common. Even for those enterpriseswith a "no Wi-Fi" policy, a Windows XP laptop with a wireless client will automatically try to connect to an SSID that it has successfully connected to before. This scenario is very common for two reasons. If the employee has connected to a Linksys, Netgear or other home or hot spot access point using the default SSID, it will automatically connect to another AP with the same SSID without the user being aware of the connection. Secondly, neighboring Wi-Fi networks can spill into the enterprise and curious users connect to these open, insecure, and distrusted networks while still connected on the wired side of the trusted network. Users may also connect to these networks if their internal network firewall does not permit POP email accounts, does not permit access to certain web sites, or they do not want their outbound traffic monitored. Whats WRONG WITH WEP? As part of the encryption process, WEP prepares a keyschedule ("seed") by concatenating the shared secret key supplied by the user of the sending station with a random-generated 24-bit initialization vector (IV). WEP specifies a shared secret 40 or 64-bit key to encrypt and decrypt the data. Some vendors also include 128 bit keys (know as "WEP2") in their products. WEP has been part of the 802.11 standard since initial ratification in September 1999. At that time, the 802.11 committee was aware of some WEP limitations; however, WEP was the best choice to ensure efficient implementations worldwide. Nevertheless, WEP has undergone much scrutiny and criticism over the past couple years. WEP is vulnerable because of relatively short IVs and keys that remain static. The issues with WEP don't really have much to do with the RC4 encryption algorithm. With only 24 bits, WEP eventually uses the same IV for different data packets. For a large busy network, this reoccurrence of IVs can happen within an hour or so. This results in the transmission of frames having keystreams that are too similar. If a hacker collects enough frames based on the same IV, the individual can determine the shared values among them, i.e., the keystream or the shared secret key. This of course leads to the hacker decrypting any of the 802.11 frames. Wireless networking Attacks MAC Address Shared Key Spoofing Attack Authentication Attacks Disassociation and Known Plaintext Deauthentication Attack attacks Monday, August 18, 2008 6 AP has list of MAC addresses that are allowed to enter the network Attacker can snif the MAC address and spoof it Disassociation/Deauthentication Attacks - wifi stations authenticate and then associate, anyone can send disassociate packets, Tools available include Omerta (simply sends disassociation for every data packet), Airjack (includes essid jack which sends a disassociation packet and then listens for association packets to find hidden SSIDs that are not broadcast, FATA_JACK (sends invalid authentication requests spoofing legitimate clients causing the aP to disassociate the client), MONKEY-JACK (deauthenticates a victim and poses as the AP when the victim returns), Void11 (floods authenticate requests to AP causing DoS) SHARED KEY AUTHENTICATION ATTACKS - authentication challenge is sent in the clear, can use the IV and keystream for false authentication, collect keystreams for man IVs, 24b IV = 24 GB for 1500B packets, all day collection and then look at the data the next day, can store all possible keystreams and then use them to decrypt any messages Known Plaintext Attack Monday, August 18, 2008 7 Wired attacker sends a message to wireless victim - information on the wired network is unencrypted , so putting the two computers capture the unencrypted and put a computer on the wireless network to capture the encrypted, so you know what the message is because you send the message, then you get the encrypted packet in the air, AP encrypts the message and transmits over the air Attacker has both plain text and encrypted text (keystream) - taking the two parts together you get the key stream Wireless Networking Attacks Reaction Attack FMS Attack Message Modification Dictionary Attack on Attack LEAP Inductive Attack Reuse IV Attack WEP Key Attacks Monday, August 18, 2008 8 Reaction attack - ICV is a linear sum => predicable Change few bits and rebroadcast (TCP acks short packets) Flip selected bits => figure out whether the Keystream bits are 0 or 1 Message Modification Attack - change the destination address to attacker’s wired node, unencrypted packet will be delivered by the AP to the wired node Inductive attack - theoritical attack, there is no tool that will do this attack, if you know N bytes of keystream, you can find n+1st byte, send a ping request with 256 variations of the n_1st byte, whichever generates a response is the correct variation. Again, theoritical, but there easier ways to get the keystream. REUSE IV ATTACK - if you have the keystream for a particular IV, you can keep using the same IV for the keystream you have WEP KEY ATTACKS - since people can’t remember or it is difcult for them to enter a 40 bit or 104 bit key, the wireless product vendors allow you to enter a passphrase, so the key is generated by a well-known pass phrase algorithm, wep_crack creates a table of keys for all dictionary words and uses them to find the key, dictionary based attack takes a few minutes FMS ATTACK - Based on a weakness of the way RC4 initializes its matrix, if a key is weak RC4 keystream contains some portions of key more than other combinations, webcrack to snif the network and analyze the output using FMS to crack the key, airsnort snifs and uses a part of FMS to find the key, other tools include dwepdum to capture packets and dwepcrack to find the WEP key DICTIONARY ATTACK ON LEAP - CISCO’s first attempt to make stronger authentication, LEAP uses MSCHAP v1 for authentication, capture the challenge and response, brute force password attack - use something like john the ripper to break the hash of the password, WPA Replacement for WEP Stronger Encryption Two versus One Monday, August 18, 2008 9 * WPA-Enterprise, a mechanism for network authentication using IEEE 802.1x and a supported EAP type, one of EAP/TLS, TTLS or PEAP; Related Content * WPA-Personal, a mechanism for using TKIP without IEEE 802.1x authentication by using a shared passphrase, intended for consumer networks. In July 2004, the IEEE approved the full IEEE 802.11i specification, which was quickly followed by a new interoperability testing certification from the WiFi Alliance known as WPA2.

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