SMS forging is a relatively new kind of high-tech felony, which uses the short message service (SMS), which is available on most mobile phones and personal digital assistants, to spoof or impersonate another user. The spoofing is often used to send viruses that can be carried from phone to phone and which can cause destructive behavior.
SMS spoofing became possible after many mobile/cellular operators had integrated their network communications with/in the Internet. So anybody could send SMS from the Internet using forms at the websites of mobile operators or even through e-mail. Unfortunately, the Internet forms designed to send SMS may have vulnerabilities that could lead hackers to be able to break the tunneling protocol that links the phones with the Internet.
Surprisingly, one can use legitimate SMS tools available on the market for spoofing. For instance, Clickatell, a provider of carrier-grade bulk SMS messaging solutions and applications that can be integrated and used immediately within a global environment, developed various software allowing users to send bulk and personalized SMS messaging to existing databases, Lotus Domino and other integrated SMS solutions. Therefore any person can purchase or even download evaluation software that would allow the individual to send a spoof SMS. Other providers such as FakeMyText and CloakText actually sell an anonymous texting service as their main service which can be used to spoof a SMS message from any international number.
There is also dedicated Open Source tool called SMS Spoof, which is a Palm OS application that allows individuals to send spoofed SMS messages. It uses a dialup connection to any EMI/UCP-compatible short message service center (SMSC) which supports the EMI/UCP protocol, as long as no authentication is required.
Every SMS sent from sender to receiver is in PDU format which is of 7bit .
07Length of the SMSC information (in this case 7 octets)
91Type-of-address of the SMSC. (91 means international format of the phone number)
72 83 01 00 10 F5Service center number(in decimal semi-octets). The length of the phone number is odd (11), so a trailing F has been added to form proper octets. The phone number of this service center is "+27381000015".
04First octet of this SMS-DELIVER message .
0BAddress-Length. Length of the sender number (0B hex = 11 dec)
C8Type-of-address of the sender number
72 38 88 09 00 F1Sender number (decimal semi-octets), with a trailing F, By changing this format at the sender side,we can spoof sender ID of the SMS.