Magecart Hackers Target Misconfigured Amazon S3 Buckets. Attackers target more than 17,000 web domains, including websites in the top 2,000 of Alexa rankings. Magecart is neither a single group nor a specific malware instead an umbrella term given to all those cyber criminal groups and individuals who inject digital card skimmers on compromised websites. Instead of making use of digital skimming code in plain JavaScript, the group has been found using a heavily obfuscated version of its card-skimmer with encrypted payloads.
Source: https://thehackernews.com/2019/07/magecart-amazon-s3-hacking.html