A security flaw in the Travis CI API has left tens of thousands of developers' user tokens and other sensitive information exposed to attack, as threat actors could use the credentials to wage attacks in cloud services, including GitHub, Amazon Web Services (AWS), and Docker Hub.

The issue was first reported as far back as 2015, but the vulnerability in the API can still be exploited to launch attacks laterally across the cloud, according to a new blog post from Team Nautilus, which notes that all free-tier users of Travis CI are at risk.

The Travis CI API is commonly used by developers to test apps, and during their research the analysts were able to access more than 770 million cleartext logs, chock-full of the kind of sensitive data that threat actors could leverage to move laterally across cloud services for malicious activity. 

"We disclosed our findings to Travis which responded that this issue is 'by design', so all the secrets are currently available," according to the post on the Travis CI API vulnerability. "All Travis CI free tier users are potentially exposed, so we recommend rotating your keys immediately."