Ex-NTU undergrad jailed 10 months for modifying stored-value cards to cheat Kopitiam of nearly $81k

(Yahoo News Singapore file photo)

SINGAPORE — A Nanyang Technological University (NTU) undergraduate used a specialised program and phone app to modify the value on four Kopitiam cards such that he never had to pay for his meals, drinks and cigarettes.

While checking his Kopitiam card at the kiosks at the outlets, 25-year-old Tee Chin Yue also found the Kopitiam card machines offered services for the top-up of Singtel pre-paid SIM cards.

He realised that he could use his modified Kopitiam card to top up SIM cards, and saw a business opportunity in charging other people for such a service. He eventually used the Kopitiam card to top up 186 pre-paid SIM cards from 67 different users.

In this manner, he caused Kopitiam to lose $80,812.41 and earned $46,170.41 for himself.

On Wednesday (1 April), Tee was jailed for 10 months on one charge of unauthorised modification of computer material which he pleaded guilty to earlier. A similar charge was taken into consideration for his sentencing. 

First modified card for free air-conditioning

Tee was a computer engineering undergraduate at NTU at the time of the offences, and first learned about the possibility of card modification while residing in an NTU hostel in 2015. 

The hostel required students to use stored-value cards to pay for air-conditioning services in their rooms. Students would need to top up these cards with cash before they could pay.

Tee, however, wanted free air-conditioning, and decided to research on how he could hack the system so that the card would register as having stored value even if he did not top it up.

The Malaysian then learned that the stored-value card was produced by a brand called Mifare. He bought a card reader, and downloaded a specialised computer program which would allow him to read and modify the contents of the card.

He also downloaded onto two mobile phones a specialised mobile phone app which had the technology to allow him to modify the card’s stored value.

Tee eventually succeeded in modifying the stored value of the card and obtaining free air-conditioning. 

Applied same method to Kopitiam cards

Later, Tee realised the same method could be used to modify the Mifare stored value cards which were used at Kopitiam food court outlets. 

He began to modify the four Kopitiam Mifare cards he had, and also changed the last four digits of the card numbers in order to avoid detection of his offences. He then used the cards to buy food, drinks and cigarettes for free.

As he checked the value of his Kopitiam card one day, he realised the kiosk offered services to top-up Singtel pre-paid SIM cards. 

“The accused saw this as a business opportunity and embarked on a scheme where he would charge money for top-ups of the pre-paid SIM cards, while using the modified Kopitiam card to effect the top-up. In such a way, the accused would earn money for the top-ups without having to pay anything himself,” said Deputy Public Prosecutor David Koh. 

Tee created an account on online marketplace Carousell with the name “singteltopup”, and advertised the service of crediting value to pre-paid SIM cards at a discount – for example, charging $8 for a top-up of $10. 

Carousell users would provide Tee with the mobile number of the pre-paid cards and how much they wanted to credit. Tee would carry out the top-ups at at Kopitiam outlets and his “customers” would pay him via bank transfers. 

Between 18 February and 13 December 2016, Tee conducted such exchanges on 137 occasions, spending $67,239.91. 

Tee’s conduct came to an end after he tried to carry out a SIM card top-up and and found out that his card had been suspended. None of his four Kopitiam cards worked and he realised that the operator might have upgraded its system. He stopped the top-up service, worried that the law would catch up to him and threw the four Kopitiam cards away. 

His offences came to light when a Kopitiam staff at the Lau Pa Sat outlet observed suspicious transactions made by another person. A police report was made on 12 December 2016 and Kopitiam conducted its own investigations. The police managed to track one of Tee’s customers and found Tee through his Carousell account.

Tee was arrested on 24 July 2017. 

Restituted sum to Kopitiam

Between 18 August 2015 and 13 December 2016, Tee wrongfully gained $46,170.41 from his unauthorised modifications. 

He bought food, drinks and cigarettes worth a total of $12,215.41 from Kopitiam outlets using the cards that he had modified. 

In total, he topped up 186 pre-paid SIM cards, as requested by 67 different SIM card users, and received $33,955 in payment from Carousell users. 

In total, Tee caused Kopitiam to lose $80,812.41. He has since restituted the sum to Kopitiam on 24 June last year. 

For unauthorised modification of computer material, Tee could have been jailed up to three months and/or fined up to $10,000.


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