It was not a phishing link or a dodgy app this time. Some of the biggest money-moving machinery in India, the quiet plumbing that shifts your UPI payment from your bank to a merchant in seconds, is what the attackers went after. An investigation published by The Economic Times on October 15 has revealed that roughly 20 Indian financial institutions, including banks, non-banking finance companies and fintech firms, were hit by a wave of cyberattacks earlier this month that struck directly at payment and loan-disbursement APIs.
The method, say investigators quoted in the report, was as clever as it was alarming. Instead of targeting customers, the attackers allegedly used stolen credentials belonging to partner banks to exploit vulnerabilities in the APIs that connect lenders, payment gateways and fintech platforms. Because the credentials were legitimate, the system treated the intruders like trusted insiders. Money moved through whitelisted infrastructure, slipping past controls that were supposed to catch exactly this kind of abuse, including customer verification checks, loan approval workflows and transaction limits.
The full extent of the damage is not yet public. What is clear is that India’s cybersecurity establishment saw this coming. CERT-In, the country’s nodal agency for responding to computer security incidents, issued an advisory on October 9 warning about the attack techniques, days before the investigation’s findings became widely known. In the days since, emergency restrictions have been placed on the vulnerable payment interfaces while the affected institutions scramble to rotate credentials and lock down access.
How the attack worked
Think of APIs as the delivery drivers of digital finance. Every time you pay with UPI, take an instant loan from a lending app, or receive money through a payment gateway, dozens of API calls ferry your data between your bank, the app and the merchant. Each call needs credentials to prove it is legitimate, much like a key card that opens a secure door.
According to the investigation, attackers got hold of the key cards. The stolen partner-bank credentials let them submit loan disbursements and payment transfers through legitimate channels, which meant the fraud looked, to the system’s eyes, like ordinary business. Investigators suspect some of the funds were funnelled into mule accounts, the classic endpoint of banking fraud, where money is quickly layered and withdrawn before anyone realises it was never authorised.
There is also a darker hint in the report: the possible use of AI-assisted hacking tools to automate the discovery of vulnerable endpoints and to craft the attack sequence. That remains unconfirmed, but if true, it would mark a worrying escalation. Automated attacks do not sleep, do not get bored and can probe thousands of endpoints for weaknesses in minutes.
Why this matters for ordinary Indians
You might never see your bank’s name in a headline about this. That is partly the point. The attacked systems sit behind the apps you use every day, and the institutions involved have every incentive to keep the incident contained. But the implications touch anyone who uses digital payments in India:
- Trust in instant lending: loan disbursements that can be triggered through stolen credentials raise hard questions about how fintech apps verify borrowers before money leaves the vault.
- Whitelisted infrastructure is a double-edged sword: the very trust networks that make UPI fast, the pre-approved channels between partners, become the attacker’s camouflage when credentials leak.
- Mule accounts still work: despite years of warnings and new account-freezing tools, the stolen money still appears to have found its way into mule accounts, the first stop in every major Indian banking fraud.
- The timing is uncomfortable: the attacks surfaced during the festive shopping season, when payment volumes spike and Diwali spending is in full swing. NPCI has already deferred its new UPI merchant charges until after Diwali, and banks are on high alert.
The good news, such as it is, is that no confirmed figure for total losses has emerged, and there is no evidence yet that customer passwords or personal login data were the entry point. This was an infrastructure attack, not a consumer one. Your UPI PIN was never the target.
What the industry is doing now
Behind the scenes, the response is following a familiar emergency playbook. CERT-In’s October 9 advisory flagged the attack patterns for every institution in the ecosystem, and the affected lenders have begun rotating API credentials, tightening maker-checker controls, where no single person can authorise a payment alone, and increasing scrutiny of beneficiary accounts.
Cybersecurity experts say the fixes go deeper than a password reset. Modern API security means zero-trust authentication, where every call is verified in real time rather than waved through because it carries the right key. It means behavioural monitoring that flags a loan disbursement at 3 AM to a brand-new account, even if the credentials check out. And it means faster information sharing across banks, because an attack pattern seen at one institution is almost certainly being tried at others.
The incident also lands at a moment of heightened global attention. South Korea’s financial regulator confirmed on October 14 that 16 of its own financial firms had been hit by hacking incidents, with roughly 100,000 cases of data leakage identified. Regulators there are now planning broader security inspections, and Indian authorities will be watching that playbook closely.
What should you actually do
Honestly, there is little an individual can do about a bank’s API keys. But the one thing you can control is speed. Check your bank statements and UPI transaction history regularly, not monthly. Turn on transaction alerts for every debit, and do not dismiss them as noise. If you spot a transaction you do not recognise, report it to your bank immediately; under RBI’s zero-liability framework, reporting unauthorised electronic transactions quickly is what protects you from bearing the loss.
The broader lesson from this episode is one India keeps relearning: the country’s digital payments revolution was built on speed and trust, and both are only as strong as the weakest credential in the chain. As UPI marches toward global expansion and instant credit goes mainstream, the attack surface grows with it. The fight is no longer about keeping hackers out of your phone. It is about keeping them out of the plumbing.
FAQs
Which institutions were affected by the cyberattacks?
The investigation reports roughly 20 Indian financial institutions, including banks, NBFCs and fintech companies. The specific names have not been publicly disclosed, and the precise aggregate loss has not been established.
What did CERT-In say about the attacks?
CERT-In issued an advisory on October 9, 2026, warning about the attack techniques used against payment and loan-disbursement APIs, ahead of the investigation’s publication on October 15.
Were customer passwords or UPI PINs compromised?
There is no evidence of that so far. The attacks targeted institutional infrastructure, using stolen partner-bank API credentials to push unauthorised transfers through legitimate, whitelisted channels.
Are my UPI payments still safe?
Day-to-day UPI payments continue to function normally, and person-to-person transfers are unaffected. Keep transaction alerts on and report anything unfamiliar to your bank immediately.
Was AI used in the attacks?
The investigation notes the possible use of AI-assisted hacking tools, but this has not been confirmed. Regulators in South Korea are separately examining whether AI played a role in attacks on 16 of its financial firms.
Informeia will update this story as banks and regulators release more details.
