OAK — OnChain Attack Knowledge

Worked example · 2026

Q1–Q2 2026 Sub-Million Exploit Cohort — 36 Incidents Across 13 Chains — Aggregate ~$9.8M

OAK Techniques observed
OAK-T9.004, OAK-T9.001, OAK-T9.002, OAK-T9.011, OAK-T10.002, OAK-T11.001
Attribution
unattributed (aggregate cohort).
Loss
Aggregate ~$9.8M across 36 incidents spanning January–May 2026, distributed across Ethereum, BSC, Base, Arbitrum, Solana, Polygon, Avalanche, Sui, Near, Bitcoin, Stellar, Dango, and Litecoin. Individual losses range from $5K to $950K. The incidents cover the full spectrum of OAK T9 Technique sub-classes at smaller scale: access-control misconfiguration (19 incidents), oracle/price manipulation (5), flash-loan-enabled exploit (3), precision-loss/donation attacks (4), cross-chain/bridge (2), key compromise (1: Zerion), and special-category (2: EIP-7702 delegation, Groth16 verifier).
Key teaching point
The Q1–Q2 2026 sub-million exploit surface demonstrates that T9.004 (Access-Control Misconfiguration) is the highest-frequency exploit class across all loss magnitudes, accounting for 19 of 36 incidents (53%). The exploit primitives are identical to those in the >$1M cohort — missing modifiers, unprotected initialisers, deprecated contracts, unvalidated inputs — but the extraction magnitude is bounded by the protocol's TVL rather than the exploit's technical severity. A missing onlyOwner modifier on a $10M-TVl protocol causes a $5M loss; the same missing modifier on a $500K-TVL protocol causes a $150K loss. The technique is identical; the dollar figure reflects the protocol's size, not the exploit's sophistication.
Corrected 2026-10-11
Bisq reclassified as a negative-miner-fee missing-validation bug (11.59 BTC, not a counterfeit client / T11.001); Aethir's $423K was an initial estimate with later user losses <$90K via transferOwnership on AethirOFTAdapter; Zerion marked DPRK/UNC1069-attributed; LML date noted as Mar 31/Apr 1; Syndicate restated as an upgrade-admin compromise ($330–380K); cohort totals adjusted.
Missing modifier / permissionless function
PRXVT (CREATE2 sybil, $97K), Aethir (<$90K user losses; $423K initial estimate), SubQuery Network ($60K), Quant ($138K), SQ Protocol ($346K)
Modifier-bypass
Molt EVM (onlySpawnerToken bypass, $127K), INK Finance (whitelist impersonation, $140K)
Unprotected initializer / uninitialized proxy
Aurellion ($456K), Renegade ($209K)
Deprecated / abandoned contract
Scallop Lend (deprecated V2 rewards, $150K)
Input-validation gap
Bisq v1 (negative miner fee, $858K), MONA (burn-address accounting, $60,950), Kipseli (flawed quoting logic, $80K), Juicebox V3 (borrowFrom spoof, $52K), Revert Lend (staked collateral, $50K)
Cross-chain gateway / bundler logic
ZetaChain GatewayEVM (6-chain, $300K), Gondi V3 (PurchaseBundler, $230K)
Special-category
Fusion by IPOR (EIP-7702 delegation abuse, $336K) — structurally adjacent to account-abstraction supply-chain surface; Veil Cash (Groth16 verifier misconfiguration, $5K) — ZK-proof verification constraint gap
Oracle misconfiguration
Ploutos Money ($390K), Singularity Finance ($413K), Sharwa.Finance ($32,850)
Spot-price / mispricing
GoonFi ($254K), LML/USDT staking protocol ($950K — largest in cohort)
Cross-chain oracle message spoofing
Stake DAO ($176K) — oracle message verification gap across Arbitrum and Base
Donation / inflation attacks
Curve LlamaLend ($240K), dTRINITY dLEND ($257K), Thetanuts Finance (first-depositor, $50K)
Negative-amount donation
Dango ($410K) — the attacker donated negative amounts (integer underflow) to manipulate the vault's accounting, a novel T9.011 sub-variant exploiting the sign of the donation rather than its magnitude
Share-accounting precision loss
Goose Finance ($8,435)
Hot wallet social engineering
Zerion Wallet ($100K) — a long-running AI-enabled social-engineering attack linked by Zerion to a DPRK actor (SEAL tied the pattern to UNC1069); structurally identical to the >$1M T11.001 cases (Step Finance, Grinex) at smaller scale. Bisq, previously filed here as a counterfeit-client case, was a missing-validation bug exploited with a modified client and has moved to T9.004.

Summary

Timeline

When Event OAK ref
2026-01-01 PRXVT: Sybil attack with CREATE2 addresses on Base; $97K extracted via address-prediction gaming T9.004 (CREATE2 address manipulation)
2026-01-06 Fusion by IPOR: EIP-7702 delegation exploit on Arbitrum; attacker leverages delegate-account capabilities; $336K T9.004 (EIP-7702 delegation abuse — structurally adjacent to smart-account supply-chain surface)
2026-01-20 ZeroLend: insolvency event on Ethereum; $371K extracted via protocol insolvency mechanism — the protocol became undercollateralised and the shortfall was extracted T9.004 (insolvency-mechanism exploit — missing solvency-check on withdrawal path)
2026-01-29 Revert Lend: staked collateral exploit on Base; $50K via collateral-valuation gap T9.004 (collateral-validation access-control gap)
2026-02-20 Veil Cash: misconfigured Groth16 verifier on Base; $5K extracted via zero-knowledge proof verification bypass — documented in full at examples/2026-02-veil-cash-groth16-verifying-key-delta-gamma-forgery.md T9.004 (ZK-verifier misconfiguration — missing constraint in proof verification)
2026-02-26 Ploutos Money: misconfigured oracle exploit on Ethereum; $390K T9.001 (oracle misconfiguration)
2026-02-28 Wise Lending V2: flashloan exploit across Arbitrum and Ethereum; $66K T9.002 (flash-loan capital acquisition)
2026-03-02 Curve LlamaLend: donation attack on Ethereum; $240K extracted via vault-share-price manipulation T9.011 (donation-attack vault-share-price manipulation)
2026-03-07 Molt EVM: onlySpawnerToken modifier hack on Base; $127K via modifier-bypass access control T9.004 (modifier-bypass access-control gap)
2026-03-09 Gondi V3: PurchaseBundler exploit on Ethereum; $230K — documented in full at examples/2026-03-gondi-purchasebundler-missing-caller-check-nft-approval-drain.md T9.004 (bundler-logic access-control gap)
2026-03-12 Stake DAO: oracle message spoofing across Arbitrum and Base; $176K T9.001 (oracle message spoofing), T10.002 (cross-chain message forgery)
2026-03-14 Goose Finance: share-accounting flaw on BSC; $8,435 via integer-arithmetic rounding error T9.011 (share-accounting precision loss)
2026-03-17 dTRINITY dLEND: deposit inflation attack on Ethereum; $257K via vault-share-price donation-and-inflation T9.011 (deposit-inflation vault manipulation)
2026-03-28 GoonFi: mispricing arbitrage on Solana; $254K T9.001 (spot-price mispricing)
2026-03-31 / 04-01 (outlets differ; Crypto Times dated 04-01) LML/USDT staking protocol: price manipulation attack on BSC; $950K — the largest incident in this cohort T9.001 (price manipulation), T9.002 (flash-loan capital)
2026-04-09 Aethir: attacker called transferOwnership on AethirOFTAdapter (BNB Chain) without authorisation and drained ATH held by the adapter; the $423K figure was an initial token-count estimate (~423,000 ATH) and Aethir's later update put actual user losses below $90K T9.004 (access-control misconfiguration)
2026-04-12 SubQuery Network: access control exploit on Base; $60K T9.004 (access-control misconfiguration)
2026-04-13 Dango: donate-negative-amounts hack on Dango chain; $410K via integer-underflow donation primitive T9.011 (negative-amount donation — integer-arithmetic boundary violation), T9.004 (missing input-validation)
2026-04-13 MONA: BurnAddress accounting exploit on BSC; $60,950 via burn-address tokenomics manipulation T9.004 (burn-address accounting logic gap)
2026-04 (week before post-mortem; exact date not given) Zerion Wallet: ~$100K taken from company hot wallets after a long-running AI-enabled social-engineering attack on team members (sessions, credentials, hot-wallet keys); Zerion linked it to a DPRK actor and SEAL tied the pattern to UNC1069 T11.001 (hot wallet social-engineering compromise)
2026-04-20 Juicebox V3: borrowFrom spoof attack on Ethereum; $52K T9.004 (borrow-function caller-authorisation bypass)
2026-04-20 Thetanuts Finance: first-depositor attack on Ethereum; $50K via vault-initialisation share-price manipulation T9.011 (first-depositor vault-share manipulation)
2026-04-22 Kipseli: flawed quoting logic on Base; $80K T9.004 (quoting-logic access-control gap)
2026-04-26 Scallop Lend: deprecated V2 rewards contract on Sui; $150K via abandoned-contract residual-value drain T9.004 (deprecated-contract anti-pattern)
2026-04-27 Singularity Finance: oracle misconfiguration exploit on Base; $413K T9.001 (oracle misconfiguration)
2026-04-27 ZetaChain: GatewayEVM contracts exploit across 6 chains (Ethereum, Base, Polygon, Arbitrum, Avalanche, BSC); $300K via cross-chain gateway access-control gap T9.004 (gateway access-control gap), T10.002 (cross-chain gateway message validation)
2026-04-28 JUDAO: flashloan exploit on BSC; $228K T9.002 (flash-loan-enabled exploit)
2026-04-28 Quant: access control exploit on Ethereum; $138K T9.004 (access-control misconfiguration)
2026-04-29 Syndicate: Commons bridge proxy on Base drained of ~18.45M SYND via a compromised upgrade admin and a malicious implementation (DarkNavy); realised value ~$330K per most outlets, ~$380K including ~$50K of other user assets; Syndicate blamed a leaked key kept in a password manager with no multisig/hardware signing on upgrades T9.004 (upgrade-control compromise; a proxy-upgrade/key-compromise tag such as T6.005 or T11.014 fits better — remap suggestion; not a message-verification bypass)
2026-05-01 Bisq v1: 11.59 BTC (~$858K) lost by 10 users when an attacker's modified client sent a negative miner fee that the trade protocol did not validate, causing the maker to compute a wrong multisig output (only open altcoin offers hit; Bisq 2, fiat trades and passive wallet funds unaffected) T9.004 (missing input validation; not a counterfeit client and not T11.001)
2026-05-01 Sharwa.Finance: oracle price manipulation on Arbitrum; $32,850 T9.001 (oracle price manipulation)
2026-05-04 SmartCredit: flashloan exploit on Ethereum; $72K T9.002 (flash-loan-enabled exploit)
2026-05-10 Renegade: unprotected initializer exploit on Arbitrum; $209K via missing initialisation guard T9.004 (unprotected initializer — missing initializer modifier)
2026-05-11 INK Finance: whitelisted-address impersonation on Polygon; $140K via whitelist-spoofing access-control bypass T9.004 (whitelist-impersonation access-control bypass)
2026-05-12 Aurellion: uninitialized proxy exploit on Arbitrum; $456K T9.004 (uninitialized proxy — missing proxy-initialisation guard)
2026-05-12 SQ Protocol: access control exploit on BSC; $346K T9.004 (access-control misconfiguration)

Incident summaries by technique family

T9.004 — Access-Control Misconfiguration (19 incidents, ~$4.0M aggregate)

The dominant exploit class in the sub-million cohort, spanning the full T9.004 sub-pattern taxonomy:

T9.001 — Oracle and Price Manipulation (5 incidents, ~$2.0M aggregate)

T9.002 — Flash-Loan-Enabled Exploit (3 incidents, ~$366K aggregate)

Wise Lending V2 ($66K), JUDAO ($228K), SmartCredit ($72K) — all follow the canonical flash-loan-capitalised atomic extraction pattern at sub-million TVL scale.

T9.011 — Precision-Loss and Donation Attacks (4 incidents, ~$967K aggregate)

T10.002 — Cross-Chain and Bridge (1 incident, ~$176K aggregate)

Stake DAO oracle message spoofing ($176K cross-chain component) is the remaining cross-chain message-verification case. Syndicate Commons bridge (~$330–380K) is an upgrade-admin compromise rather than a message-verification gap and is listed under T9.004 above.

T11.001 — Key and Client Compromise (1 incident, ~$100K aggregate)

Discussion

The Q1–Q2 2026 sub-million cohort is the statistical baseline for DeFi exploit frequency: 36 incidents in ~20 weeks, averaging 1.8 per week, with T9.004 (Access-Control Misconfiguration) as the dominant class (~53%). The exploit primitives are technically identical to those in the >$1M cohort; the loss magnitude reflects the protocol's TVL, not the exploit's novelty.

Several incidents in this cohort are technically notable despite their smaller dollar figures:

Dango's negative-amount donation ($410K) is the cohort's most technically interesting exploit: the attacker exploited an integer-arithmetic boundary violation to "donate" a negative amount, which underflowed into a value-extracting operation. This is a novel T9.011 sub-variant — the donation primitive is preserved (value transferred directly to the vault), but the sign is inverted via integer underflow, turning a deposit into a withdrawal. The incident suggests that donation-attack mitigations (virtual shares, dead shares, minimum-deposit enforcement) must also validate the sign of the donation amount, not just its magnitude.

Veil Cash's Groth16 verifier misconfiguration ($5K) is the cohort's most technically sophisticated exploit despite its trivial extraction: a missing constraint in the zero-knowledge proof verification logic allowed the attacker to forge a proof that the verifier accepted. The incident is a T9.004 sub-pattern applied to a ZK-verifier — the verifier's constraint set is the access-control surface, and a missing constraint is structurally identical to a missing require statement. The $5K extraction reflects the protocol's early-stage TVL, not the exploit's technical severity — a fully-launched protocol with the same verifier bug would have lost orders of magnitude more.

Bisq's negative miner fee (11.59 BTC, ~$858K) is a missing-validation bug in a peer-to-peer trade protocol: the taker-supplied miner fee was not checked for negative values, so a modified client could make the maker compute a wrong multisig output. It is not a counterfeit-client or supply-chain incident; Bisq reported no additional fund-stealing path in its wider review.

Fusion by IPOR's EIP-7702 delegation exploit ($336K) is structurally adjacent to the account-abstraction (T13) surface: EIP-7702 allows EOAs to delegate execution to smart-contract code, effectively creating temporary smart accounts. An attacker who exploits the delegation mechanism can execute code in the context of any EOA that has set a delegation. The incident is a leading indicator of the EIP-7702 exploit surface and is classified under T9.004 pending further characterisation of the EIP-7702-specific technique class.

Public references

Techniques demonstrated (6)