Security researchers have discovered that about 7.26 million records linked to users of mobile payments app BHIM were left exposed to the public by a website.

The exposed data included sensitive information such as names, dates of birth, age, gender, home address, caste status and Aadhaar card details, among others, said the report from VPN review website vpnMentor.

"The scale of the exposed data is extraordinary, affecting millions of people all over India and exposing them to potentially devastating fraud, theft, and attack from hackers and cybercriminals," the security researchers from vpnMentor wrote in a blog post on Sunday.

Offered by the National Payments Corporation of India (NPCI), the app BHIM, or Bharat Interface for Money, was launched in 2016.

BHIM app UPI india
Millions of users, who have downloaded the BHIM app, may not be aware of the fact that they have authorised the NPCI to track their phone calls.Google Play Store

NPCI denies data breach

In a statement on Monday, the NPCI said that "there has been no data compromise at BHIM App."

"We have come across some news reports which suggest data breach at BHIM App. We would like to clarify that there has been no data compromise at BHIM App and request everyone to not fall prey to such speculations. NPCI follows high level of security and an integrated approach to protect its infrastructure and continue to provide a robust payments ecosystem," said the NPCI.

In its report, vpnMentor also said that the website that leaked the data was developed by a company called CSC e-Governance Services LTD. in partnership with the Indian government.

The issue was resolved late last month after the researchers contacted India's Computer Emergency Response Team (CERT-In) twice in a month's time.

Zomato hacking
BHIM data leakedReuters

Details of the hack

"In this case, the data was stored on an unsecured Amazon Web Services (AWS) S3 bucket," the researchers said, adding that S3 buckets are a popular form of Cloud storage across the world but require developers to set up the security protocols on their accounts.

"We reached out to the website's developers to notify them of the misconfiguration in their S3 bucket and to offer our assistance. After not receiving a reply, we contacted India's Computer Emergency Response Team (CERT-In), which deals with cybersecurity in the country," they added.

It appears CSC established the website connected to the misconfigured S3 bucket to promote BHIM usage across India and sign up new merchant businesses, such as mechanics, farmers, service providers, and store owners onto the app, according to the research led by vpnMentor's Noam Rotem and Ran Locar.

The volume of exposed data which was first discovered by the security researchers on April 23 amounted to 409GB.

"It's difficult to say precisely, but the S3 bucket seemed to contain records from a short period: February 2019. However, even within such a short timeframe, over 7 million records had been uploaded and exposed," said the report.

"The exposure of BHIM user data is akin to a hacker gaining access to the entire data infrastructure of a bank, along with millions of its users' account information," it added.

(With inputs from IANS)