Kraken Security Labs has said that a “large number” of Bitcoin ATMs are vulnerable to hacking as the administrators never changed the default admin QR code. In a Sept. 29 blog post, Kraken posted research from its Security Labs team which found that there are “multiple hardware and software vulnerabilities” in the General Bytes BATMTwo ATM range. “Multiple attack vectors were found through the default administrative QR code, the Android operating software, the ATM management system and even the hardware case of the machine,” the post read.