Facebook is fertile ground for scammers in many countries where the world’s largest social network is largely favored, and Vietnam is no exception.

While a number of scams have targeted Vietnamese Facebook users over the last year, a list of the three most viral tricks was published on the forum for “white hat” hackers of local Internet security firm Bkav on December 30.

The term "white hat" in Internet slang refers to an ethical computer hacker, or a computer security expert, who specializes in penetration testing and in other testing methodologies to ensure the security of an organization's information systems.

Topping the list is a scam known as the “Uncle Viettel,” which dupes users into joining a false promotional program claimed to be offered by military-run Viettel, Vietnam’s largest mobile network operator.

Scammers using “Uncle Viettel” spread messages on Facebook, citing the revelation of “my uncle who works for Viettel” that the telco is offering a special program that will increase the value of the prepaid cards users enter by 10 to 20 times.

To enjoy the promotion, users are instructed to enter a string of code, which scammers say is “the secret code to validate that you are eligible for the program,” on their mobile phones, including the number of a new prepaid card and a mobile phone number.

The code is in fact intended to transfer all the money of the prepaid card to the account of the scammers.

A number of light-minded users have fallen victim to the trick. Others have had their Facebook accounts hacked, which then automatically posted the scam message onto the Timeline of all of their friends, helping to spread the fraud at lightning speed.

Viettel has had to officially announce that it never launched such a promotional campaign as revealed by the “Uncle Viettel” on Facebook.

The man allegedly behind the “Uncle Viettel” scam has been arrested and charged with swindling, Hanoi police announced Thursday.

Do Van Dung, hailing from the central province of Quang Tri, was captured on charges of "swindling to appropriate assets,” according to Le Hong Son, head of the police unit in charge of fighting hi-tech criminals.

The 20-year-old has raked in more than VND30 million (US$1,398) from the scam, Son said.

The second most widespread Facebook scam in Vietnam is the “chibi drawing,” which lured users into clicking on a link to a website that will automatically create a chibi portrait from their own photos.

Chibi is a Japanese slang word meaning "short person" or "small child." In manga (Japanese comics), the term chibi has mostly been conflated with the "super deformed" style of drawing characters with oversized heads, intending to depict scenes which are cute and humorous.

A screen capture that shows a spam message of the "chibi drawing" scam

Once victims click on the link, a malicious software program will be secretly installed on their computers, which will automatically spread the scam massages among their Facebook friends, and like or follow pages owned by the scammers.

The last scam of the top three is the “fake news site,” according to Bkav.

Scammers set up fake websites that look identical to authentic newswires and share articles with shocking or sensational titles on Facebook, luring victims to click to read the false news.

Those who click on the links will be redirected to a malicious website which could install malware on the victims’ computers, or steal their Facebook accounts.

Vietnam has 36 million Internet users, with nearly 25 million using Facebook, The Saigon Times Online said, citing findings released in May 2014 by Danish market research agency Epinion.

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