Signature replay across chains → token drain

§ Context

Assumed environment: target dApp uses permit-style off-chain signatures. The signing structure omits chainId or verifyingContract — a multi-chain deployment shares the same approvals.

§ Steps

1. 01
   transferFrom the approved tokensExfiltration

   T1041— Exfiltration Over C2 Channel
2. 02
   Find permit() endpoint without chainId bindingReconnaissance

   W-RECON-API-DISCO— API Endpoint Discovery
3. 03
   Submit same signature on other chainCredential Access

   W3-SIG-REPLAY— Signature Replay
4. 04
   Capture victim signature (mempool / off-chain)Credential Access

   W3-SIG-REPLAY— Signature Replay

§ References

• T1041Exfiltration Over C2 Channel

§ Frequently asked

What is the "Signature replay across chains → token drain" attack path?

EIP-2612 permit() signed without chainId / domain separator binding. Capture the off-chain signature on one chain and replay it on another to drain ERC-20 approvals. It chains 4 steps drawn from real-world offensive-security techniques.

What starting position does this attack require?

The first step is transferFrom the approved tokens (T1041) — a exfiltration primitive. Assumed environment: target dApp uses permit-style off-chain signatures.

What is the final impact of this kill-chain?

The final step lands on Capture victim signature (mempool / off-chain) (W3-SIG-REPLAY), which falls under Credential Access. From here, an operator typically pivots into post-exploitation or maintains persistence.

How can defenders detect or prevent this attack?

Detection and prevention vary per step. Refer to each linked MITRE ATT&CK entry under "References" — every technique on that page lists defensive controls, detection telemetry, and known threat-actor usage.

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