Over 7 million records of BHIM UPI app users were breached, including scans of Aadhaar cards, caste certificates, proof of residence, PAN cards, professional certificates and degrees, according to a report by VpnMentor. The breach included lists of BHIM’s merchants and up to 1 million individual users, along with their UPI handles.

VpnMentor’s research team, led by Noam Rotem and Ran Locar, discovered the breach. According to AP News, Rotem is an Israeli security researcher, who most recently pointed out a breach in an app used by Israel’s ruling conservative party. Rotem and Locar work on behalf of VpnMentor, and have exposed multiple security vulnerabilities.

The data, totaling to 409 GB, was stored on an misconfigured Amazon Web Services S3 bucket belonging to cscbhim.in and was publicly accessible. The website is developed by CSC e-Governance Services Ltd, along with the Ministry of Electronics and Information Technology (MEITY). VpnMentor discovered the breach on April 23, and it was closed nearly a month later on May 22. The firm first contacted CERT-in, India’s nodal agency for cybersecurity threats, on April 28. The firm contacted CSC e-Governance Services on May 5. It contacted CERT-in again on May 22, after which vulnerability was finally closed.

The leaked documents contain sensitive personal information. For instance, caste certificates include name, gender, religion, father’s name, and taluk. The list of merchants and users linked them with their profession and UPI handles. Apart from address, gender, and father’s name, Aadhaar also includes biometrics.

BHIM is a UPI payments app developed by the National Payments Corporation of India (NPCI), a private body funded by public and private sector banks, which regulates UPI and other digital payments. NPCI has denied any breach, stating that “there has been no data compromise at BHIM App” and dismissed reports as speculation. We have reached out to CERT-in for details and comment.

According to VpnMentor, the bucket was made for promotion of BHIM, and to get new merchants such as “mechanics, farmers, service providers, and store owners onto the app”. “It’s difficult to say precisely, but the S3 bucket seemed to contain records from a short period: February 2019,” the firm added. “The website was being used in a campaign to sign large numbers of users and business merchants to the app from communities across India,” VPN Mentor said.

BHIM accounted for just 1% of all UPI transactions in April. BHIM has seen over 136 million app downloads, as of May 7. The NPCI, which developed the BHIM app, does not give information on the number of virtual payment addresses (VPAs) created and the number of accounts linked to BHIM.