Incident Overview
The Ukrainian hacker group Coinhoarder stole more than $50 million worth of cryptocurrency from the well-known cryptocurrency wallet Blockchain.info, according to a report by Cisco’s information security subsidiary Talos.
The report describes how hackers used a "very simple" but very dangerous technique to deceive victims. Hackers buy cryptocurrency-related keyword ads on Google’s search engine, “poison” users’ search results, and then steal assets from cryptocurrency wallets. This means that when people search for keywords such as "blockchain" or "bitcoin wallet" on Google, they will see links to malicious websites masquerading as legitimate websites.
These malicious links may be "blockchien.ino/wallet" or "block-clain.info". After clicking on these links, the user is taken to a landing page that mimics the real website. According to Cisco's report, genuine websites rank lower than malicious links in Google's search engine rankings.
Incident Report
Protocol Information
Market Context at Time of Hack
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.
What Auditors Should Check
If you're auditing a protocol with similar architecture to Blockchain.com, these are the critical security checks that could have prevented this incident (February 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.
Free TrialRelated Attack Classes
The technique used in this hack maps to these vulnerability classes in our security curriculum:
Sources & References
Learn to Prevent the Next Blockchain.com
The Blockchain.com hack is one of many attacks that skilled auditors are trained to detect before deployment. Master real exploit patterns and defense techniques with hands-on Web3 security training.