A type of malware, known as a “clipper,” takes advantage of a user’s tendency to copy and paste addresses of online cryptocurrency wallets.
Since these addresses consist of long strings of characters, when copying and pasting, users leave the information on their clipboard.
This malware can then intercept the content of the clipboard and replace it surreptitiously with what the attacker wants to subvert, said Lukas Stefanko, a malware researcher at ESET in a post. In the case of a cryptocurrency transaction, the affected user might end up with the copied wallet address quietly switched to one belonging to the attacker.
This malware first made its rounds in 2017 on the Windows platform and was spotted in shady Android app stores in the summer of 2018. In February 2019, ESET discovered a malicious clipper on Google Play, the official Android app store.
Cryptocurrency stealers that rely on altering the clipboard’s content can be considered established malware. ESET researchers discovered one hosted on download.cnet.com, one of the most popular software-hosting sites in the world. In August 2018, the first Android clipper was discovered being sold on underground hacking forums and since then, this malware has been detected in several shady app stores.
The clipper we found lurking in the Google Play store, detected by ESET security solutions as Android/Clipper.C, impersonates a legitimate service called MetaMask, Stefanko said. The malware’s primary purpose is to steal the victim’s credentials and private keys to gain control over the victim’s Ethereum funds. However, it can also replace a Bitcoin or Ethereum wallet address copied to the clipboard with one belonging to the attacker.