One of the things that happens with many companies that start adopting DevOps is that they release new features constantly. They publish their lists of changes, and they try to attract customers and grow their businesses. They may make some mistakes, but they fix those quickly and keep pushing forward. That's the idea, and it works well.
However, many of the developers (and most managers), don't think about the security side of their changes. This piece looks at the way hackers and criminals view DevOps, often using release notes and feature changes as a target to focus their efforts. In this way, they exploit holes and vulnerabilities in software to attack data storage. The examples include S3 buckets of storage and Elasticsearch, which is notoriously poorly secured by many people.
I'm sure there are hacks that also expose relational data stores and NoSQL stores, but those are often more secure and harder to directly attack. Certainly, hackers do get credentials and can query data, it's more often I hear about data breaches from other sources than direct relational database access. SQL Injection is definitely still an issue, and I hope that more and more developers are learning patterns that avoid these vulnerabilities.
DevOps works. I think it's great. However, it's not enough to trust developers to build features without including static code analysis, pen testing, and other security evaluations before you release code. Often developers can build features just as fast with good patterns as bad. Use automation to catch bad patterns and force developers to learn new ones.
Also, avoid letting developers implement data stores out of convenience and speed. Ensure that strong security practices, long passwords, service accounts, secrets, and more are implemented from the start. It's easy to shortcut these, but it's also harder to explain to customers and investors why we didn't do better.
If you're a developer, the main thing to keep in mind is that you will often be the scapegoat for these issues. Upper management might not support you and pressure you to move faster, but when there are issues, they'll also be quick to blame you and let you go first. Push back and ensure that you have the tools and the process to evaluate if you are building problematic code. Always use long passwords, and document what you do for others to follow.
And if your boss insists on cutting corners, get that in writing. It might not save your job, but that documentation has served me well in the past when issues come to light.