I don’t believe any proof of blame will be uncovered in the short term concerning the Equifax breach, though plenty of fingers will be pointed in a variety of directions.  It will take time and sound forensic analysis before we really know the truth.  The following are a few more recent articles detailing more of the what/when/how/why of this situation:

https://krebsonsecurity.com/2017/09/the-equifax-breach-what-you-should-know/

http://www.zdnet.com/article/equifax-blames-open-source-software-for-its-record-breaking-security-breach/

https://threatpost.com/apache-foundation-refutes-involvement-in-equifax-breach/127910/