A number of Amazon Web Services (AWS) clients have reportedly been given warnings that their private content could be accessed by malicious hackers.

According to the BBC, security researchers posted ‘friendly warnings’ to the AWS servers, with the majority of the warnings blaming misconfigured settings for making the information vulnerable.

The BBC reports that it found almost 50 warnings posted to Amazon’s cloud data storage service’s servers, many having more than one warning uploaded to them. The broadcaster says it has passed on the list of sites that had received warnings to Amazon.

Security experts have been predominantly scanning for mistakes in servers supporting Amazon’s Simple Storage Service (S3).

Over the last 18 months alone, misconfigured S3 data stores – or buckets – have left private information from Uber, Verizon, WWE, Dow Jones, Booz Allen Hamilton, Alteryx, and three data mining companies exposed.

Amazon has said that the default configuration for the S3 service keeps data private, and the main management screen even uses a ‘traffic light’ system to show which buckets are public and which are more secure. In addition, it said that not all public buckets are wrongly configured, as some make the information available for collaborative purposes.