Opinions expressed are solely my own and do not express the views or opinions of my employer
Hafnium/UNC2452 used novel techniques that abused and took advantage of the adoption to cloud technologies without understanding the full implications and architecture.
Microsoft has made a push in recent years to Office 365 and as a result many organizations now have hybrid cloud environments, whether they know it or not.
How is this relevant to Zero-Trust?
The spate of attacks has revealed weaknesses and tactics that pen-testers and adversaries can exploit against a hybrid cloud or zero trust environment. In a Zero trust environment there is still trust relationship between the Identity provider and Service provider. By attacking the cryptography protections in this trust relationship, UNC2452 was able to launch sophisticated attacks that often went undetected. Tokens generated by the Identity provider are trusted by the service provider. UNC2452 by forging tokens was able to abuse this trust relationship to bypass controls normally enforced when accessing Services. Through forged tokens they were able to short circuit the normal authentication piece by directly authenticating to the Service provide via tokens bypassing the Identity provider.
Great what does this mean?
For defenders, it is important to get good AAA telemetry. This means getting good logging from your Identity provider, and Service provider. Logs to track authentication, authorization, and auditing. This is a lot easier said than done.
Implementing zero trust can provide gains to an organization by lowering the overall risk by "reducing or removing implicit trust in networked systems by addressing network identity, endpoint health, and data flows." (NIST) However, it can also mean introducing a single point of failure. An attacker that can compromise the identity manager can gain access to multiple resources. If the identity provider is based in the cloud, how much trust do you place in them? What if your cloud identity provider was breached, what are the impacts to your organization? While I believe many cloud providers provide better patching and maintenance than organizations, the risk is non-zero.
References:
https://csrc.nist.gov/News/2022/planning-for-a-zero-trust-architecture-white-paper