Entries Tagged 'GSM/CDMA' ↓
August 24th, 2007 — GSM/CDMA
According to Global System for Mobile Communication (GSM Standard), the size of each SMS is limited to 160-characters in order to avoid overloading in the standard forward-and-response operation of the SMS server. Larger content of SMS can be sent but they will be segmented over multiple messages, which lead to extra charges among the mobile phone users.
Therefore Euzer Technologies Sdn Bhd has invented a novel and powerful SMS compression formula which we have filed patent at Intellectual Property Corporation of Malaysia (MyIPO) at 15th June 2007. With the 50% compression ratio that can be achieved by ZMS, mobile consumers can send up to 280 characters in a single SMS.
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August 23rd, 2007 — GSM/CDMA
In an earlier post we saw how GSM networks are jammed when the SMS traffic increases. Now some smart kids can use this loop hole to attack GSM networks and cause service outage in targeted areas. This is very much similar to DOS (Denial of service) attacks in computer networks.
Even though such a possibility exists, no one can bring down the entire service down. But its very much possible to bring down certain areas of a network, lets say an area covered by a tower.
The first step is collecting mobile numbers of subscribers in that area. Attacker can use many innovative schemes to collect mobile numbers. Some methods are described here.
Once you have enough numbers in a particular region or under a tower you can start sending SMS messages to all those numbers simultaneously. An SMPP gateway is needed for this. Many companies are providing gateways.
With the help of some spoofing techniques and zombie servers an attack can be launched quite easily. Zombie servers can bypass almost all operator spam detection mechanisms. In india, bulk sms is a huge market and I dont think there are any spam detection mechanisms implemented.
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August 23rd, 2007 — GSM/CDMA
Most providers assign certain number series to certain places. All the SIMs sold at a particular location at a particular period of time can be in the same series. With a little bit of research we can identify potential numbers in a location.
Another method is to gain access to corporate databases, where customer numbers will be stored. Modern banks provide SMS alerts, and they are a good place to start looking. If you have a friend inside its really easy pulling up mobile numbers.
Another place to look is social networks, but will require some amount of programming skills. Many provide their mobile numbers in their orkut profiles. A small tool can dig out all the mobile numbers in a particular community, or a particular friends list.
Some advanced techniques would be to use a mobile worm or a virus, which can read contact lists from mobile phones and send them to a central server without the knowledge of the user. Some bluetooth worms can do this.
Once you have enough numbers with you, you need to refine the list by finding out the genuine numbers. This can be achieved by sending a test message with a fake sender ID to all the numbers and wait for delivery reports. All delivered numbers can be used for the attack.
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August 18th, 2007 — GSM/CDMA
SMS traffic is doubling in every two years. Operators used to see this as a new revenue source. Many companies started offering services around SMS. But this explosive growth of SMS has started to created problems, mainly a degradation of the voice services.
Every operators are facing service problems during holidays and festival seasons just because of the large volume of SMS messages that are being sent. During New year almost every network will be jammed from 11:45 to 12:15. Every subsriber will be busy. This is not because everyone is calling up each other, but because the SMS traffic is blocking the voice services.
GSM networks use control channels and voice channels for handling calls and SMS messages. The control channel is used to handle SMS messages and also to setup calls. Once the call setup is finished the call proceeds using the voice channel.
Control channels have far lesser bandwidth than voice channels.
When lots of messages are pushed into the network the control channels will become busy and no control channel will be available for call setup. So all the voice services fail.
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August 3rd, 2007 — GSM/CDMA
“The Parlay Group is a consortium formed to develop open, technology-independent application programming interfaces (APIs) that enable the development of applications that operate across converged networks. Parlay integrates internet multimedia networks and intelligent networks (IN) with IT applications via a secure, measured, and billable interface and has been widely deployed in telecoms networks globally. By releasing developers from underlying code, networks, and environments, Parlay’s open APIs and web services allow for innovation within the enterprise. These new, portable, network-independent applications are connecting the IT and telecom worlds, generating new revenue streams for network operators, application service providers (ASPs), and independent software vendors (ISVs).
”
I found this in their website (www.parlay.org)
These guys are a non profit organization which aims to develop open APIs so that applications can communicate across multiple telecom networks.
The TWSS (Telecom web services server) from IBM uses the parlay APIs.
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