Deleting handset data won’t protect you

Rohit Khanna,TNN | Aug 9, 2014, KOLKATA: Deleting handset data may not protect your photos and call and browsing history, warn ethical hacking experts. You have to overwrite them to erase everything. 

The file system on a cellphone or PDA is the same as a computer's hard drive. If a file is deleted, the data is not actually overwritten. Experts say phone data can be retrieved easily even after you delete them. 

Vulnerability of discarded handsets has come to light after several data theft cases surfaced in Kolkata recently, said Sandeep Sengupta, CEO of Indian School of Ethical Hacking. The trend is likely to increase with the ever-increasing use of smart-phones, he cautioned. 

Police agree the threat is real. "There have been cases where data was stolen from discarded computer hard-disks. It can also be stolen from mobile phones," said a senior officer. 

When you delete data from a handset, it still remains on the memory card or the phone's internal memory. Deleting data only changes the index of the file system or the file's pointers. If the phone falls into expert hands, all sensitive data — like passwords, key logs and browser history — can be retrieved. 

"Data is not lost unless you overwrite it. Merely deleting data will not work. Even choosing 'factory reset' will not work in some cases," said Sengupta. Talking to reporters on the sidelines of information technology conclave ICT East organized by CII on Friday, he said that methods like 'inspect elements' are often used by hackers to retrieve data from discarded mobile phones. 

Is there a way to exchange your old mobile safely? The first step is to set 'factory reset'. You can download apps and devices that wipe the memory clean. In some phones, the option is called 'hard reset'. In fact, you can save or transfer data to a new device before deleting it from the old one. 

The next step should be to remove or erase SIM and SD cards. SD cards often contain photos and other sensitive information. Even after the 'wipe' method is used, SIM card or SD cards may retain information. Experts say there is mobile device management software which can be downloaded to overwrite data. 

The data stored in a phone and PDA is actually stored in flash memory and is retained even if the device's battery is drained or removed. While 'hard reset' might return the software to factory-fresh condition, for some of the phones it needs to be taken to the technicians to erase stored data completely.