OAK — OnChain Attack Knowledge

Worked example · 2021-20

2021–2024 Rekt.Uncovered Incidents Cohort

OAK Techniques observed
OAK-T9.001, OAK-T9.002, OAK-T9.004, OAK-T9.007, OAK-T9.011, OAK-T5.003, OAK-T5.005, OAK-T10.002, OAK-T11.001
Attribution
unattributed (aggregate cohort of 21 incidents by multiple operators).
Loss
Aggregate ~$159.2M across 21 incidents spanning 2021–2024, distributed across Ethereum, BSC, Polygon, Arbitrum, RSK, Terra, xDai, and Base. Individual losses range from $330K (Merlin Labs) to $31.4M (MonoX). The 2021 batch alone accounts for ~$109.5M (69% of aggregate), dominated by BSC yield-aggregator forks exploited via flash-loan price manipulation during May–July 2021. The 2022–2024 batch (~$49.7M) reflects more varied exploit surfaces on mainnet protocols.
Key teaching point
These 21 incidents complete the 2020–2024 rekt.news leaderboard coverage. The 2021 batch is dominated by BSC yield-aggregator forks (bEarn, BurgerSwap, Autoshark, Merlin Labs — four PancakeSwap/PancakeBunny derivatives exploited via flash-loan price manipulation within two weeks of each other in May 2021), reflecting the low-barrier-to-entry fork culture where unaudited BSC DeFi contracts deployed without meaningful security review were drained serially. The 2022–2024 batch shifts toward mainnet protocols with more varied exploit surfaces: contract upgrade regressions (Astroport, Unizen), context-verification bypasses (Superfluid), parameter-ordering authorization breaks (Deus DAO), and collateral-minting logic flaws (Shezmu). Several of these (Astroport, Deus DAO, Merlin Labs) were third-exploit-on-same-protocol cases — the structural signal is that a previously exploited protocol has elevated re-exploit probability.

Summary

Timeline

When Event OAK ref
2021-05-12 XToken: flash-loan-enabled exploit of xSNXa and xBNT wrapper contracts; $24M via manipulated price oracle feeding the wrapper's mint/redeem logic T9.002
2021-05-17 bEarn Fi: BSC flash-loan vault-share manipulation; $18M via PancakeSwap BNB/BUSD price manipulation feeding bVault strategy contracts T9.002
2021-05-24 Autoshark: PancakeBunny-fork flash-loan exploit on BSC; $745K via SHARK/WBNB pool price manipulation in yield-compounding vault T9.002
2021-05-28 BurgerSwap: BSC DEX pair-manipulation attack; $7.2M via fake token deployed to manipulate swap math and drain paired assets T9.002
2021-06-16 Alchemix: alETH vault debt-assignment accounting bug on Ethereum; $6.5M — ETH deposited as collateral for alETH minting had debt set to zero, allowing collateral withdrawal without repayment T9.004
2021-06-29 Merlin Labs (3rd exploit): third BSC exploit in rapid succession; $330K via remaining vulnerability in staking/compounding contract after two prior patches T9.004
2021-07-10 Anyswap (later Multichain): bridge signature-verification bypass; $7.9M via forged validator signature accepted due to insufficient MPC signing verification T10.002
2021-07-15 Bondly Finance: deployer-key compromise enabling infinite mint; $5.9M — 373M BONDLY minted and dumped on market via compromised deployer wallet T11.001 + T5.003
2021-07-30 Levyathan Finance: BSC yield aggregator validation gap; $1.5M via basic contract-logic errors in strategy/vault interaction on unaudited BSC fork T9.004
2021-11-30 MonoX Finance: single-sided AMM price manipulation on Polygon; $31.4M via repeated vDIN swap-loop inflating internal pool valuation to drain other assets T9.001
2022-02-08 Superfluid: host-contract ctx verification bypass on Ethereum/xDai; $8.7M via calldata injection in deleteAnyFlowBad — isCtxValid enforced only on SuperApp callbacks not host-trusted data T10.002
2022-10-04 Sovryn: RSK Bitcoin-sidechain lending-contract logic flaw; $1.1M via collateral-accounting contract allowing withdrawal without proper backing T9.004
2022-10-11 TempleDAO: missing oldStaking parameter validation in StaxLPStaking.migrateStake() on Ethereum; $2.3M via attacker-supplied malicious staking contract address T9.004
2023-02-17 Dexible: missing caller authorization in selfSwap() on Arbitrum/Ethereum; $2M via crafted calldata draining any user who had approved the Dexible contract T9.004
2023-05-05 Deus DAO (3rd exploit): burnFrom parameter-ordering authorization break on Arbitrum/BSC/Ethereum; $6.5M via transposed msgSender/account arguments in _allowances array enabling unauthorized burn on any DEI approver T9.004
2024-03-08 Unizen: contract-upgrade unverified external call on Ethereum; $2.1M via gas-optimization upgrade introducing call path without target/calldata verification T9.004
2024-03-28 Prisma Finance: migration-contract flash-loan accounting exploit on Ethereum; $11.6M via flash-loan-funded manipulation of trove-manager accounting T9.002
2024-07-20 ETHTrustFund: classic rug pull on Base; $2.1M via team treasury drain after accumulating investor deposits on novel L2 T5.005
2024-07-30 Astroport: known vuln reintroduced on Terra; $6.4M via ibc-hooks reentrancy (allowing illegitimate token minting) patched April 2024, accidentally reintroduced in June 2024 upgrade T9.007
2024-09-20 Shezmu: vault collateral-type logic flaw on Ethereum; $4.9M via vault accepting permissionlessly-mintable collateral token — attacker minted worthless collateral, deposited, borrowed real ShezUSD T5.003
2024-09-25 Bedrock: uniBTC vault exchange-rate arithmetic miscalculation on Ethereum; $2M via ETH→BTC conversion logic error allowing depositors to receive more uniBTC than warranted T9.011

Public references

  • rekt.news leaderboard — 295 articles, extracted 2026-05-15
  • Each protocol's rekt.news article (slugs listed above)
  • Halborn analysis — Deus DAO burnFrom parameter-ordering vulnerability

Techniques demonstrated (9)