The devs are responsible for the code, but the CSO is accountable for it. So it's the CSOs job to make sure the devs do their work well because it's the CSOs ne

The devs are responsible for the code, but the CSO is accountable for it. So it's the CSOs job to make sure the devs do their work well because it's the CSOs neck on the line if it isn't. That should take the form of the CSO making sure there's a budget for training the devs, security certification for senior devs who'll writing important aspects of the app, code review by the CSO and security certified devs, hiring in third party auditors, and so on. Hiring a dev who's "Secure Developer Certified" might be an option too, but there would still need to be all the above checks in place to make sure they're writing decent code, so looking for the certification at the point of hiring is a bit redundant.