Hackers of India

Uncovering Azure’s Silent Threats: A Journey Into Cloud Vulnerabilities

By  Nitesh Surana  on 23 Sep 2023 @ Nullcon


Presentation Material

Abstract

Cloud service providers offer Machine Learning as a Service platform, enabling companies to leverage the power of scalability & reliability while performing ML operations. However, with the massive adoption of such AI/ML systems worldwide where companies would be seeking to build services like ChatGPT, the security posture of the platform itself often may go unnoticed. We investigated Azure ML, a managed MLaaS from Microsoft. We found five vulnerabilities over three broad classes of security issues, namely: [CVE-2023-23312] Insecure logging of sensitive information: We found five instances of credentials leaking in cleartext on Compute Instances due to insecure usage of open-source components and insecure system design of how the environment was being provisioned. [CVE-2023-28312] Sensitive information disclosure: We found a case of exposed APIs in cloud middleware leaking sensitive information from Compute Instances. Network-adjacent attackers could leverage the vulnerability after initial access to laterally move or snoop in on the commands executed using a Jupyter terminal on a Compute Instance. Achieving stealthy Persistence: While reversing cloud middleware to decipher their functionality, we found two ways to achieve persistence in AML environments. An attacker could fetch the Storage Account access key and the Azure AD JWT of the system-assigned managed identity assigned to the Compute Instance, even from non-Azure environments. The logs generated while fetching the credentials from non-Azure environments would not be distinguishable from the legitimate logs generated from the Azure environment, making this technique of persistence, stealthy. Through this talk, the attendees will learn about the different issues found in AML. As we take a deep dive into the security issues, we will demonstrate various analysis techniques we adapted to while researching the service, giving the attendees a glimpse of how managed services like AML can be assessed when there are blurred lines in the shared responsibility model of security {of, in} the cloud.