ABSTRACT
Mobile communication has been readily available for several years, and is major business today. It provides a valuable service to its users who are willing to pay a considerable premium over a fixed line phone, to be able to walk and talk freely. Because of its usefulness and the money involved in the business, it is subject to fraud. Unfortunately, the advance of security standards has not kept pace with the dissemination of mobile communication.
Some of the features of mobile communication make it an alluring target for criminals. It is a relatively new invention, so not all people are quite familiar with its possibilities, in good or in bad. Its newness also means intense competition among mobile phone service providers as they are attracting customers. The major threat to mobile phone is from cloning.
Cell phone cloning is a technique wherein security data from one cell phone is transferred into another phone. The other cell phone becomes the exact replica of the original cell phone like a clone. As a result, while calls can be made from both phones, only the original is billed. Though communication channels are equipped with security algorithms, yet cloners get away with the help of loop holes in systems. So when one gets huge bills, the chances are that the phone is being cloned.
This paper describes about the cell phone cloning with implementation in GSM and CDMA technology phones. It gives an insight into the security mechanism in CDMA and GSM phones along with the loop holes in the systems and discusses on the different ways of preventing this cloning. Moreover, the future threat of this fraud is being elaborated
CONTENTS
S.NO. / CHAPTER / PAGE NO.INTRODUCTION
HOW CELL PHONE WORKS?
WHAT IS CELL PHONE CLONING?
WHEN DID CELL CLONING START?
HOW IS CELL CLONING DONE?
METHODS TO DETECT CLONED PHONE ON NETWORK
ARE OUR CELL PHONES SECURED?
HOW TO KNOW THAT THE CELL HAS BEEN CLONED?
ROLE OF SERVICE PROVIDERS TO COMBAT CLONING FRAUD?
HOW TO PREVENT CELL CLONI\NG?
SOME FACTS AND FIGURES
FUTURE THREATS
CONCLUSION
REFERENCES
INDEX
CHAPTER-1
INTRODUCTION
Cloning is the creation of an organism that is an exact genetic copy of another. This means
that every single bit of DNA is the same between the two!
Remember Dolly the lamb, cloned from a six-year-old ewe in 1997, by a group of researchers at the Roslin Institute in Scotland? While the debate on the ethics of cloning continues, human race, for the first time, are faced with a more tangible and harmful version of cloning and this time it is your cell phone that is the target.
Millions of cell phones users, be it GSM or CDMA, run at risk of having their phones cloned. As a cell phone user if you have been receiving exorbitantly high bills for calls that were never placed, chances are that your cell phone could be cloned. Unfortunately, there is no way the subscriber can detect cloning. Events like call dropping or anomalies in monthly bills can act as tickers.
According to media reports, recently the Delhi (India) police arrested a person with 20 cell- phones, a laptop, a SIM scanner, and a writer. The accused was running an exchange illegally wherein he cloned CDMA based cell phones. He used software named Patagonia for the cloning and provided cheap international calls to Indian immigrants in West Asia.
CHAPTER-2
HOW CELL PHONE WORKS?
Cell phones send radio frequency transmissions through the air on two distinct channels, one for voice communications and the other for control signals. When a cellular phone makes a call, it normally transmits its Electronic Security Number (ESN), Mobile Identification Number (MIN), its Station Class Mark (SCM) and the number called in a short burst of data. This burst is the short buzz you hear after you press the SEND button and before the tower catches the data. These four things are the components the cellular provider uses to ensure that the phone is programmed to be billed and that it also has the identity of both the customer and the phone. MIN and ESN is collectively known as the ‘Pair’ which is used for the cell phone identification.
When the cell site receives the pair signal, it determines if the requester is a legitimate registered user by comparing the requestor's pair to a cellular subscriber list. Once the cellular telephone's pair has been recognized, the cell site emits a control signal to permit the subscriber to place calls at will. This process, known as Anonymous Registration, is carried out each time the telephone is turned on or picked up by a new cell site.
ESN -The ESN (Electronic Serial Number) is the serial number of your cellular telephone.The ESN is transmitted to the cell site and used in conjuction with the NAM to verify that you are a legitimate user of the cellular system.
MIN- The MIN (Mobile Identification Number) is simply the phone number of the
cellular telephone.
CHAPTER-3
WHAT IS CELL PHONE CLONING?
Cell phone cloning is copying the identity of one mobile telephone to another mobile telephone.
Usually this is done for the purpose of making fraudulent telephone calls. The bills for the calls go to the legitimate subscriber. The cloner is also able to make effectively anonymous calls, which attracts another group of interested users.
Cloning is the process of taking the programmed information that is stored in a legitimate mobile phone and illegally programming the identical information into another mobile phone. The result is that the "cloned" phone can make and receive calls and the charges for those calls are billed to the legitimate subscriber. The service provider network does not have a way to differentiate between the legitimate phone and the "cloned" phone.
Cloning of mobile phones is the act of copying the subscriber information from one phone onto the other for purposes of obtaining free calls. The other cell phone becomes the exact replica of the original cell phone like a clone. As a result, while calls can be made from both phones, only the original is billed.
Cloning occurs most frequently in areas of high cell phone usage -- valet parking lots, airports, shopping malls, concert halls, sports stadiums, and high-congestion traffic areas in metropolitan cities.
Figure 1. Cellular phone cloning
CHAPTER-4
WHEN DID CELL CLONING START?
The early 1990s were boom times for eavesdroppers. Any curious teenager with a £100 Tandy Scanner could listen in to nearly any analogue mobile phone call. As a result, Cabinet Ministers, company chiefs and celebrities routinely found their most intimate conversations published in the next day's tabloids
Cell phone cloning started with Motorola "bag" phones and reached its peak in the mid 90's with a commonly available modification for the Motorola "brick" phones, such as the Classic, the Ultra Classic, and the Model 8000.
GSM– Global System for Mobile Communications. A digital cellular phone technology based on TDMA GSM phones use a Subscriber Identity Module (SIM) card that contains user account information. Any GSM phone becomes immediately programmed after plugging in the SIM card, thus allowing GSM phones to be easily rented or borrowed.Operators who provide GSM service are Airtel,Hutch etc.
CDMA - Code Division Multiple Access. A method for transmitting simultaneous signals over a shared portion of the spectrum. There is no Subscriber Identity Module (SIM) card unlike in GSM.Operators who provides CDMA service in India are Reliance and Tata Indicom.
Both GSM and CDMA handsets are prone to cloning. Technically, it is easier to clone a CDMA handset over a GSM one, though cloning a GSM cell phone is not impossible. There are also Internet sites that provide information on how one could go about hacking into cell-phones.
Cloning CDMA Cell Phones - Cellular telephone thieves monitor the radio frequency spectrum and steal the cell phone pair as it is being anonymously registered with a cell site. The technology uses spread-spectrum techniques to share bands with multiple conversations. Subscriber information is also encrypted and transmitted digitally. CDMA handsets are particularly vulnerable to cloning, according to experts. First generation mobile cellular networks allowed fraudsters to pull subscription data (such as ESN and MIN) from the analog air interface and use this data to clone phones. A device called as DDi, Digital Data Interface (which comes in various formats from the more expensive stand-alone box, to a device which interfaces with your 800 MHz capable scanner and a PC) can be used to get pairs by simply making the device mobile and sitting in a busy traffic area (freeway overpass) and collect all the data you need. The stolen ESN and EMIN were then fed into a new CDMA handset, whose existing program was erased with the help of downloaded software. The buyer then programs them into new phones which will have the same number as that of the original subscriber.
Cloning GSM Phones -GSM handsets, on the contrary, are safer, according to experts. Every GSM phone has a 15 digit electronic serial number (referred to as the IMEI). It is not a particularly secret bit of information and you don't need to take any care to keep it private. The important information is the IMSI, which is stored on the removable SIM card that carries all your subscriber information, roaming database and so on. GSM employs a fairly
sophisticated asymmetric-key cryptosystem for over-the-air transmission of subscriber information. Cloning a SIM using information captured over-the-air is therefore difficult, though not impossible. As long as you don't lose your SIM card, you're safe with GSM. GSM carriers use the COMP128 authentication algorithm for the SIM, authentication center and network which make GSM a far secure technology.
GSM networks which are considered to be impregnable can also be hacked. The process is simple: a SIM card is inserted into a reader. After connecting it to the computer using data cables, the card details were transferred into the PC. Then, using freely available encryption software on the Net, the card details can be encrypted on to a blank smart card. The result: A cloned cell phone is ready for misuse
IS FIXED TELEPHONE NETWORK SAFER THAN MOBILE PHONE?
The answer is yes. In spite of this, the security functions which prevent eavesdropping and unauthorized user are emphasized by the mobile phone companies. The existing mobile communication networks are not safer than the fixed Telephone networks. They only offer protection against the new forms of abuse.
SECURITY FUNCTIONS OF THE GSM AND CDMA -As background to a better understanding of the attacks on the GSM and CDMA network the following gives a brief introduction to the Security functions available in GSM. The following functions exist: Access control by means of a personal smart card (called subscriber Identity module, SIM) and PIN (personal identification number), Authentication of the users towards the network carrier and generation of a session key in order to prevent abuse. Encryption of communication on the radio interface, i.e. between mobile Station and base station, concealing the users’ identity on the radio interface, i.e. a temporary valid Identity code (TMSI) is used for the identification of a mobile user instead Of the IMSI.
CHAPTER – 5
HOW IS CELL CLONING DONE?
Cloning involved modifying or replacing the EPROM in the phone with a new chip which would allow you to configure an ESN (Electronic serial number) via software. You would also have to change the MIN (Mobile Identification Number). When you had successfully changed the ESN/MIN pair, your phone was an effective clone of the other phone. Cloning required access to ESN and MIN pairs. ESN/MIN pairs were discovered in several ways:
- Sniffing the cellular
- Trashing cellular companies or cellular resellers
- Hacking cellular companies or cellular resellers
Cloning still works under the AMPS/NAMPS system, but has fallen in popularity as older clone able phones are more difficult to find and newer phones have not been successfully reverse-engineered.
Cloning has been successfully demonstrated under GSM, but the process is not easy and it currently remains in the realm of serious hobbyists and researchers.
When placing a call, the phone transmits both the ESN and the MIN to the network. These were, however, sent in the clear, so anyone with a suitable scanner could receive them. The eavesdropped codes would then be programmed into another phone, effectively cloning the original subscription. Any calls made on this cloned phone would be charged on the original customer. See figure2.
WHAT IS PATAGONIA?
Patagonia is software available in the market which is used to clone CDMA phone. Using this software a cloner can take over the control of a CDMA phone i.e. cloning of phone. There are other Software’s available in the market to clone GSM phone. This software’s are easily available in the market. A SIM can be cloned again and again and they can be used at different places. Messages and calls sent by cloned phones can be tracked. However, if the accused manages to also clone the IMEI number of the handset, for which software’s are available, there is no way he can be traced.
Figure 2. Cellular cloning.
CHAPTER -6
METHODS TO DETECT CLONED PHONES ON NETWORK
Several countermeasures were taken with varying success. Here are various methods to detect cloned phones on the network:
Duplicate detection - The network sees the same phone in several places at the same time. Reactions include shutting them all off so that the real customer will contact the operator because he lost the service he is paying for, or tearing down connections so that the clone users will switch to another clone but the real user will contact the operator.
Velocity trap - The mobile phone seems to be moving at impossible, or most unlikely speeds. For example, if a call is first made in Helsinki, and five minutes later, another call is made but this time in Tampere, there must be two phones with the same identity on the network.
RF (Radio Frequency)- fingerprinting is originally a military technology. Even nominally identical radio equipment has a distinguishing ``fingerprint'', so the network software stores and compares fingerprints for all the phones that it sees. This way, it will spot the clones with the same identity but different fingerprints.
Usage profiling. - Profiles of customers' phone usage are kept, and when discrepancies are noticed, the customer is contacted. Credit card companies use the same method. For example, if a customer normally makes only local network calls but is suddenly placing calls to foreign countries for hours of airtime, it indicates a possible clone.
Call counting - Both the phone and the network keep track of calls made with the phone, and should they differ more than the usually allowed one call, service is denied.
PIN codes - Prior to placing a call, the caller unlocks the phone by entering a PIN code and then calls as usual. After the call has been completed, the user locks the phone by entering the PIN code again. Operators may share PIN information to enable safer roaming.
Figure 3.Duplicate Detection
CHAPTER -7
ARE OUR CELL PHONES SECURED?
Too many users treat their mobile phones as gadgets rather than as business assets covered by corporate security policy. Did you realize there's a lucrative black market in stolen and "cloned" Sim cards? This is possible because Sims are not network specific and, though tamper-proof, their security is flawed. In fact, a Sim can be cloned many times and the resulting cards used in numerous phones, each feeding illegally off the same bill.
But there are locking mechanisms on the cellular phones that require a PIN to access the phone. This would dissuade some attackers, foil others, but might not work against a well financed and equipped attacker. An 8-digit PIN requires approximately 50,000,000 guesses, but there may be ways for sophisticated attackers to bypass it.
With the shift to GSM digital - which now covers almost the entire UK mobile sector - the phone companies assure us that the bad old days are over. Mobile phones, they say, are secure and privacy friendly.
This is not entirely true. While the amateur scanner menace has been largely exterminated, there is now more potential than ever before for privacy invasion.
The alleged security of GSM relies on the myth that encryption - the mathematical scrambling of our conversations - makes it impossible for anyone to intercept and understand our words. And while this claim looks good on paper, it does not stand up to scrutiny.
The reality is that the encryption has deliberately been made insecure. Many encrypted calls can therefore be intercepted and decrypted with a laptop computer.
CHAPTER -8
HOW TO KNOW THAT THE CELL HAS BEEN CLONED?
Frequent wrong number phone calls to your phone, or hang-ups.
Difficulty in placing outgoing calls.
Difficulty inretrieving voice mail messages.
Incoming calls constantly receiving busy signals or wrong numbers. Unusual calls appearing on your phone bills
CHAPTER -9