Attackers can use various different methods in attempt to "hijack" your cellphone or PDA. They can steal your personal information, misuse your service, put your privacy in danger, etc. Here are some common ways in which this can happen:
Enticing You to a Malicious Website
PDAs and cell phones are often targets of phishing scams where an attacker can create a fake website that may appear to be a legit online banking website and when you visit, the malicious code runs and does its job. Attackers also send text messages to cell phones, supposedly from a legitimate company, which may try to convince you to visit a site where you may be enticed into providing personal or sensitive information or download malware infected files.
Using Your Cell Phone or PDA in an Attack
When an attacker attacks and gain control of your service, your cell phone or PDA becomes a “zombie” phone or “zombie” PDA, which will be used to attack others. It helps the attacker in hiding his or her identity and increasing the number of targets.
Gaining Access to Your Account Information
Most modern phones allow users to perform certain transactions such as paying for utility and credit card bills and more. An attacker, who successfully gains access to a phone, may be able to read your personal account information then misuse or sell it.
Abusing Your Service
The number of text messages you can send or receive is often limited in cell phone plans and an attacker can spam you by sending a message, which can incur your extra charges. An attacker can phreak your service, which means he or she will be able to use your service, without you knowing about this, while putting all the costs on you.