A version of a popular JavaScript library for Node.js contained malicious code for several months that enabled digital attackers to access users’ bitcoin wallets.

At the end of November, GitHub user Ayrton Sparling (aka FallingSnow) reported that someone had added malicious code to EventStream, a toolkit for Node.js that makes it easier for developers to create and work with data streams. The code became active in September when right9ctrl, the new owner of the library, published version 3.3.6 of EventStream. This version came with a dependency called flatmap-stream, which contained the malware.

The creator of flatmap-stream designed the module to steal bitcoin from Copay wallets, a wallet app designed by BitPay. The module then used Node Package Manager (NPM) to transfer the stolen bitcoins to a server located in Kuala Lumpur, Malaysia. NPM has since removed the backdoor.

According to Trend Micro, millions of developers downloaded the malicious code, since the module’s use of encryption enabled flatmap-stream to go undetected for more than two months.

Attacks Against Bitcoin Wallets on the Rise

Digital attackers aren’t new to the idea of stealing bitcoins out of users’ wallets. As reported by Carbon Black, these heists contributed to the loss of $1.1 billion in bitcoin during the first five months of 2018.

Some bad actors have also made a lot of money emptying cryptocurrency wallets. For instance, CoinDesk reported an attack that stole $78 million worth of bitcoin from the wallets of NiceHash, a cryptocurrency mining marketplace. News of this attack came less than a year after Cisco Talos uncovered CoinHoarder, a threat group that netted $50 million in three years by phishing blockchain.info users for access to their wallets.

How to Protect Against Cryptocurrency-Related Threats

Security professionals can help protect against bitcoin-related threats by training employees not to open suspicious emails designed to steal their credentials for cryptocurrency wallets and other accounts. They should also develop an endpoint security strategy built around artificial intelligence (AI) and machine learning to help defend against threats like crypto-mining malware.

Sources: Trend Micro, Carbon Black, CoinDesk, Cisco Talos