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Anatomy of the Bybit hack: when the UI is the exploit

How attackers manipulated a signing interface to drain a $1.5B cold wallet — and why the same human-layer class threatens exchanges and enterprises alike.

Abstract security interface illustrating a compromised cryptocurrency signing workflow
AN3 · Offensive Research · · 12 min read

The Bybit incident wasn't a novel smart-contract bug. It was a signing-layer attack — the kind that bypasses every automated scanner because the exploit lives in what the operator believes they approved.

What happened

Attackers compromised the cold-wallet signing flow by injecting a malicious UI layer between the operator and the actual transaction payload. The interface displayed benign-looking transfer details while the underlying signature authorized a full drain.

Why it matters beyond crypto

The same attack class appears in:

  • Enterprise code-signing pipelines
  • CI/CD approval workflows
  • Privileged access management consoles

If a human signs what they see rather than what the system executes, you have a signing-layer vulnerability — regardless of stack.

What we recommend

  1. Independent verification — hash the payload out-of-band before signing
  2. Hardware isolation — signing keys never touch general-purpose workstations
  3. Transaction simulation — run every signature through a read-only replay before broadcast
  4. Operator training — assume the UI is hostile until proven otherwise

This brief is part of AN3 Intel Brief — research from operators who break things for a living.