Special offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy.

iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more

A study by Tim Hall and Remo Stieger estimates that 72 flash-loan attacks caused $1.211 billion in losses between February 2020 and July 2024. That is a defined historical estimate—not a current running total or a count of every DeFi exploit. Flash loans supplied attackers with temporary capital; weaknesses in price feeds or protocol logic made the attacks possible.

What the $1.211 billion figure counts

The estimate comes from Hall and Stieger’s peer-reviewed Journal of Financial Crime article, accepted and listed as in press on August 7, 2026. The study records 72 flash-loan attacks and $1.211 billion in associated losses from February 2020 through July 2024. Across the same period, the researchers identified 254 successful DeFi attacks overall, with $6.568 billion in losses. The flash-loan incidents are a subset of that broader total, not an additional amount. The University of Winchester’s study record gives the figures and study period.

The researchers say they scanned 20.63 billion blockchain transactions across Ethereum, Base, Optimism, Arbitrum, BNB Chain, Avalanche, and Polygon, using SyntiFi’s on-chain risk intelligence engine. Those are the study’s stated dataset and method; they should not be read as proof that every chain or every attack was captured. Incidents after July 2024 are outside the measurement window.

Special offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy.

How a flash loan can be used in an attack

A flash loan lets a borrower obtain cryptocurrency without collateral, provided the loan and any required fee are repaid within the same blockchain transaction. If repayment does not happen, the transaction generally reverts, so the borrowing does not persist as a conventional unpaid loan.

#1 Best Overall
Sale
Ledger Nano X - Classic Crypto Wallet with Bluetooth
  • Effortlessly build your crypto portfolio via the all in one Ledger Wallet app: buy, sell, send, receive, swap, stake and more across popular blockchains. 15,000+ coins & tokens in a single dashboard. Keep a close eye on the market. Compare service providers. Track performance. Get timely alerts. Build your portfolio with confidence.
  • Effortlessly build your crypto portfolio via the all in one Ledger Wallet app: buy, sell, send, receive, swap, stake and more across popular blockchains. 15,000+ coins & tokens in a single dashboard. Keep a close eye on the market. Compare service providers. Track performance. Get timely alerts. Build your portfolio with confidence.
  • Enjoy Bluetooth connectivity, iOS access, and hours of battery use with this mobile-first, secure backup signer. Freedom you can depend on.
  • Genuine Check: confirm your signer is authentic during setup with the Ledger Wallet app.
  • Protect your signer: keep it in mint condition at all times with a bespoke Pod or Case to avoid scratches and everyday wear and tear.

The loan itself is a financing tool, not a vulnerability. An attack occurs when borrowed funds help exploit a flaw in a DeFi protocol. For example, an attacker might use borrowed tokens to move a token’s price on one venue, then rely on a vulnerable protocol that takes that distorted price as trustworthy. The attacker can extract value from the protocol, reverse the price-moving trade, and repay the loan before the transaction ends. This is one illustrative price-manipulation path, not a description of all 72 incidents. The University of Winchester’s explanation describes this kind of sequence.

Two broad weaknesses, 14 attack types

Hall and Stieger classify the 14 attack types they identified into two broad families:

Rank #2
Sale
TANGEM Crypto Wallet Pack of 3 – Trusted Cold Storage Hardware Wallet
  • Proven security at scale: Over 9 years and millions of cards issued with no known remote hacks, while military‑grade EAL6+ security keeps your private keys locked inside the chip. Your cryptocurrencies stay strongly protected from online attackers.
  • Tap once to manage your entire crypto wallet across 90 blockchains - no USB cables or Bluetooth, no batteries, no setup. Access 14,100+ coins & tokens, DeFi, NFTs, and staking instantly from your phone
  • Smart backup: Use your second Tangem Wallet as your Backup keys with end‑to‑end encryption; no more papers, pictures. If one card is lost, the remaining can still restore full access, with an optional seed phrase available for advanced users.
  • Engineered to last up to 25 years: Waterproof (IP69K), shockproof and tested for extreme temperatures from −25°C to 50°C. A durable cold wallet with long‑term protection and independently audited security.
  • Trusted by 6 million users worldwide (4.9 App Store, 4.8 Google Play) - buy, sell, swap, stake, and spend cryptocurrency directly. The secure offline storage wallet designed for how people actually use crypto wallets
  • Price-feed manipulation: An attacker distorts or takes advantage of a price source that a protocol uses to value assets or make decisions.
  • Protocol-logic exploits: An attacker takes advantage of a flaw in the rules or implementation of a protocol—for example, how it handles a function, a sequence of transactions, or a governance action.

A flash loan can make either kind of exploit more powerful by briefly providing substantial capital. But having access to borrowed funds does not, by itself, create the vulnerable price feed or faulty protocol logic.

Special offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy.

What secondary reporting says about the distribution of losses

Decrypt’s October 6, 2026 report on the study adds detail about where losses occurred and how the mix of attacks changed. These breakdowns are reported by Decrypt as findings from the paper, rather than figures independently confirmed here against the full article text.

Rank #3
TANGEM Crypto Wallet Pack of 2 – Trusted Cold Storage Hardware Wallet
  • Proven security at scale: Over 9 years and millions of cards issued with no known remote hacks, while military‑grade EAL6+ security keeps your private keys locked inside the chip. Your cryptocurrencies stay strongly protected from online attackers.
  • Tap once to manage your entire crypto wallet across 90 blockchains - no USB cables or Bluetooth, no batteries, no setup. Access 14,100+ coins & tokens, DeFi, NFTs, and staking instantly from your phone
  • Smart backup: Use your second Tangem Wallet as your Backup keys with end‑to‑end encryption; no more papers, pictures. If one card is lost, the remaining can still restore full access, with an optional seed phrase available for advanced users.
  • Engineered to last up to 25 years: Waterproof (IP69K), shockproof and tested for extreme temperatures from −25°C to 50°C. A durable cold wallet with long‑term protection and independently audited security.
  • Trusted by 6 million users worldwide - buy, sell, swap, stake, and spend cryptocurrency directly. The secure offline storage wallet designed for how people actually use crypto wallets
  • More than 80% of flash-loan losses were on Ethereum, according to Decrypt’s account of the study.
  • Four attack types—price-oracle attacks, donate-function logic exploits, reentrancy attacks, and one governance attack—accounted for more than 81% of losses.
  • The reported share of losses from logic exploits rose from 28% in February 2020–January 2022 to 55% in February 2022–July 2024.

These figures describe different cuts of the study’s historical dataset. In particular, the shift in logic-exploit share compares two periods within the study window; it does not establish what the distribution has been since July 2024. Decrypt’s report attributes the detailed breakdowns to Hall and Stieger’s paper.

Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Support on Ko-Fi

What the findings do—and do not—show

The study’s central security lesson is that a flash loan can amplify an exploit, but the protocol weakness is the crucial opening. A transaction-level borrowing rule limits how long funds are borrowed; it does not guarantee that the protocols touched by a transaction use reliable prices or correctly enforce their own logic.

Rank #4
DCENT Hardware Wallet | Biometric Cold Storage, Bluetooth, Multi-Crypto
  • EAL5+ CERTIFIED SECURE ELEMENT + FINGERPRINT PROTECTION — Your private keys stay encrypted offline on a certified EAL5+ chip, the same security tier used in EMV bank cards. Built by DCENT, securing crypto since 2018. Fingerprint authentication adds a second layer no PIN-only wallet can match.
  • 10,000+ ASSETS NATIVE ON 100+ BLOCKCHAINS — Hold Bitcoin, Ethereum, XRP, Solana, Cardano, popular stablecoins (USDT, USDC), and NFTs in one wallet. No third-party apps, no fragmented setup — every supported asset works straight out of the box.
  • TAP-TO-SIGN MOBILE EXPERIENCE — Pair your wallet with the DCENT mobile app over Bluetooth. Manage tokens, review transactions, and access in-app swap features directly from your phone — no cables, no desktop required.
  • WEB3 & dAPP ACCESS VIA METAMASK — Connect to MetaMask and other browser extension wallets to manage NFTs, claim airdrops, and access dApps. A large screen and intuitive 4-button interface keep every transaction clearly visible before you sign.
  • SEAMLESS FIRMWARE UPDATES & 30-DAY MONEY-BACK GUARANTEE — Apply security updates without resetting your wallet or migrating funds. Backed by Amazon's 30-day money-back guarantee — your purchase is risk-free.

The totals are also bounded by the study’s stated dates, chains, and detection approach. They are useful for understanding the scale and reported patterns of attacks observed in that analysis, not for claiming a complete global tally of DeFi losses. As Professor Tim Hall of the University of Winchester put it, “We now are seeing crimes that we have never seen before and ones that are capable of stealing mind-boggling sums of money, often in the tens of millions of dollars.”

Special offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy.

Quick Recap

Best Value
Trezor Safe 7 Crypto Hardware Wallet with Bluetooth for Android/iOS/Desktop
  • Dual-chip architecture for maximum protection: The next-gen, fully auditable TROPIC01 chip works alongside a certified EAL6+ Secure Element—completely NDA-free—to deliver radically transparent, industry-leading defense against physical attacks.
  • Quantum-ready security: Get protection against future threats with the first-ever hardware wallet designed with quantum-ready architecture.
  • See every detail with confidence: Our largest high-resolution color touchscreen makes it easy to navigate your assets, review transactions and manage your coins with clarity.
  • Wireless freedom with encrypted Bluetooth control: Manage, buy, swap and stake securely using Trezor Suite on desktop or mobile. Qi2-compatible wireless charging keeps your Trezor powered up. No cables required—security meets convenience.
  • Works seamlessly with Android, iOS and desktop: Connect wirelessly or via USB-C to your phone or computer. Manage your crypto anywhere with our companion Trezor Suite app.

Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.