It’s a theft that went unnoticed, lurking in the depths of the blockchain for five years. According to the latest revelations from Arkham Intelligence, the Bitcoin mining pool LuBian was the victim of a hack in December 2020 that resulted in the loss of $3.5 billion in BTC — 90% of its assets at the time. This is an all-time record in terms of the amount stolen in crypto.
The biggest crypto hack has just been discovered, and it involves a Bitcoin mining pool
For a long time, the biggest hack in the crypto world was the Ronin bridge hack in 2022, which amounted to approximately $624 million. Ultimate proof that bridges are a sensitive source of liquidity, this sad event was relegated to second place in the rankings a few months ago, in February, when the crypto exchange Bybit suffered a sophisticated attack that cost it a modest $1.4 billion.
These are colossal sums, the result of increasingly sophisticated attacks. And yet, the biggest haul ever stolen in the history of crypto may well have slipped under the radar several years ago. According to the firm, LuBian, one of the largest Bitcoin mining pools—which controlled 6% of the hashrate in 2020—had $3.5 billion worth of BTC stolen in December 2020, representing 90% of its assets.
It should be noted that this information has only just been discovered by Arkham Intelligence, and that this theft went unnoticed for many years.
As on-chain data shows, LuBian has since contacted the hacker numerous times, sending messages via Bitcoin’s OP_Return feature, such as “let’s go through [email protected] to discuss the return of the assets and your reward” and “Message from LuBian. To the whitehat who is holding our assets, you can contact us.”
Whitehat or real hack? The mystery remains. In any case, the BTC held on the hacker’s addresses has not been moved since.
Real attack or false flag?
Many questions remain unanswered in this case: Why didn’t the attacker(s) sell any of the BTC? Dumping billions of dollars worth of Bitcoin is no easy feat, but the hackers could have used crypto mixers or other similar methods over time. Furthermore, why would the potential white hat hacker save the funds and never return them, especially with a reward at stake?
What’s more, these BTC transfers took place only a few months before LuBian completely shut down its Bitcoin mining operations. Although the company operated discreetly, we know that it was run by Chinese miners and that most of its machines were located in Iran and China.
The attack took place in December 2020, and both countries banned Bitcoin mining in the following year: China launched a nationwide crackdown on the activity from May to September 2021 (when it was finally declared illegal), while Iran banned mining in May 2021.
The timing is surprising, leading some observers to believe that this could be a false flag attack to keep the mined BTC out of circulation without having to answer to the authorities.
According to Arkham Intelligence, the theft was the result of a brute force attack on LuBian’s private keys.
Who is right? It is still too early to say.
