Electrum Hack

TOTAL LOST $949K
Low Access Control

Summarize with AI

ChatGPT Perplexity Claude Grok
Affected Chain 2018 Incident surface
Recovered - No recovery reported
All-Time Rank #832 By amount stolen
Auditors 1 Prior security audit

Incident Overview

The hacker setup a whole bunch of malicious servers.

The hacker's wallet:

https://www.blockchain.com/btc/address/1MkM9Q6xo5AHZkLv2sTGLYb3zVreE6wBkj

If someone's Electrum Wallet connected to one of those servers and tried to send a BTC transaction, they would see an official-looking message telling them to update their Electrum Wallet, along with a scam URL:

https://user-images.githubusercontent.com/29142493/50359293-8780b500-055c-11e9-8cfd-83b342edeffb.png

"There is an ongoing phishing attack against Electrum users. Our official website is https://electrum.org Do not download Electrum from any other source." - Electrum stated.

This is classified as a Access Control Attacks . Compare similar hacks →

Incident Report

Protocol / Project Electrum
Date of Incident
Attack Technique Access Control
Classification Other
Primary Source View Post-Mortem #1 View Post-Mortem #2

Protocol Information

Protocol Type Derivatives
Official Website electrum.org/
Protocol Twitter/X @ElectrumWallet
Team Anonymous
Source Code Unverified

Market Context at Time of Hack

Token Categories
Mineable Medium of Exchange Wallet Layer 1
Protocol Links
GitHub Reddit

What the Attacker Needed to Succeed

Understanding the prerequisites for this type of attack helps auditors identify protocols that are most at risk and helps developers build better defenses.

Technical Knowledge Operational-security tradecraft (phishing, malware, leaked seed phrases, or insider access) to obtain treasury signing authority
Capital Required Minimal capital - only enough to cover gas while draining the compromised accounts
On-Chain Access Valid signing authority over the compromised wallets / multisig signers, allowing direct transfer of funds or stake authorization
Target Reconnaissance Identification of Electrum's high-value treasury accounts and the authority / multisig structure controlling them
Execution Speed Speed to drain the compromised accounts before the team detects the breach and revokes signing authority or freezes the assets
Obfuscation Plan A strategy to launder and move stolen funds - typically through mixers, cross-chain bridges, or decentralized DEX swaps to resist tracing

What Auditors Should Check

Could this have been caught in audit? Likely — with a thorough Access Control audit checklist and test coverage
Audited by Audit Report 1 — still lost $949K. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to Electrum, these are the critical security checks that could have prevented this incident (December 2018).

  • Verify all logic paths related to Access Control are guarded by proper access controls and input validation - see the Access Control Attacks attack class for patterns
  • Review privileged functions (owner, admin, governance) for potential abuse vectors - centralization risks should be documented and bounded with timelocks or multi-sigs

Master these auditing techniques with hands-on labs and real exploit scenarios in the Smart Contract Hacking course.

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Security Audit History

Related Attack Classes

The technique used in this hack maps to these vulnerability classes in our security curriculum:

See all Access Control Attacks examples →

Access Control Attacks

Sources & References

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