Google is taking a step further towards securing Android smartphones by 
introducing Android L, which is built on Samsung's Knox technologies [1].

The Knox enhances the security of the smartphone by resorting to the 
following security technologies:

-          TPM, implementing static root of trust

-          ARM TrustZone, providing hardware mechanism in support of TPM

-          SE-Android, introducing mandatory access control for better 
security

-          Linux Container or other light-weight virtualization 
technologies, implementing separate domains for enterprise run-time 
environment and personal run-time environment

Without further elaborating the aforementioned technologies, it is 
concluded that Knox provides a secure platform for smartphones so that they 
may be used in mission-critical applications, especially in pursuit of BYOD 
in enterprise environment.

However, it is still vulnerable to memory based rootkit attacks [6]: After 
trusted boot of the SE-Linux (i.e. the kernel of SE-Android), memory based 
rookit may still be introduced to kernel due to vulnerabilities, etc. Such 
kind of attacks is beyond the TPM’s scope. If lucky, the rootkit may 
inherit the highest security label of the bugged code running in the 
kernel, bypassing any security mediation. 

Simply put, it is hard to detect any security compromises if the detection 
code runs within the same kernel it is intended to protect [5]. 
Fortunately, academic researchers already found a way that may take 
advantage of virtualization for further protection [2]. Specifically, 
virtual machine introspection (VMI) technology may be leveraged to provide 
real-time inspection of systems' health conditions. Moreover, such 
technology has already been implemented in some use cases [3][4], sans 
mobile platforms.

The suggested improvement on the security architecture of Knox and Android 
L is to introduce a hypervisor (like Xen), beneath the SE-Android.  
Furthermore, 
a light-weight agent is running in Dom0, side by side with the SE-Android. 
It takes advantage of VMI (like XenAccess) to inspect the health of 
SE-Android by collecting the statistics of key elements in the kernel (like 
hash value of system calls table, etc.), and passing them on to the backend 
MDM servers, through a secure connection. The MDM servers host the actual 
analytics engine and carry out weight-lifting.

This way, even if the kernel space of SE-Android is corrupted, the agent is 
able to detect the changes due to corruption.
References 
   
   1. Android L builds on Samsung’s Knox fortifications
   2. A Virtual Machine Introspection Based Architecture for Intrusion 
   Detection
   3. Insider Threat Detection on the Windows Operating System Using 
   Virtual Machine Introspection
   4. Changing the Game for Anti-Virus in the Virtual Datacenter
   5. Root Out Rootkits An inside look at McAfee Deep Defender
   6. Security Challenges in Virtualized Environments

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