Talk to any enterprise that has embraced DevOps and are trying to ensure security is adequately integrated into the organization and they'll likely say the challenge is twofold: tools and culture. Moreover, the most difficult of those two is culture.
Article Link: http://feedproxy.google.com/~r/BusinessInsightsInVirtualizationAndCloudSecurity/~3/34JEFF-uEbc/building-devsecops-culture