BOOMERANG: Exploiting the Semantic Gap in Trusted Execution Environments

Contents

1. Introduction

2. Folder Structure

   2.1 Static Analysis Tool
   2.2 Proof of Concept Exploits
   2.3 Cooperative Semantic Reconstruction
   2.4 Papers
   2.5 Presentation

3. Contact

4. Impact

5. Coming Soon

1. Introduction

BOOMERANG , a class of vulnerabilities that stem from the semantic gap between the non-secure and secure worlds. BOOMERANG is a type of confused deputy attack, wherein a user-level application in the non-secure world can leverage a TA to read from or write to non-secure world memory that it does not own, including the untrusted OS’s.

More specifically, the malicious user-level application can send inputs to the TA, which are not properly checked, that will trick the TA in to manipulating memory locations that should otherwise be inaccessible to the malicious application. BOOMERANG vulnerabilities can be used to steal or corrupt data in other user-level applications, or, in the worst case, completely compromise the untrusted OS.

We found exploitable BOOMERANG vulnerabilities in four TEE implementations. These vulnerabilities were detected using a combination of manual analysis and an automated static analysis tool, which is capable of locating potential vectors for exploiting BOOMERANG in a given TA. We were able to leverage vulnerabilities in two commercial TEE implementations to create proof-of-concept exploits.

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2. Folder Structure

We now describe the different folders in this repo, along with their purpose.

2.1 Static Analysis Tool

We created a static analysis technique to locate exploitable BOOMERANG flaws using simulated execution, which we implemented using the angr static analysis and reverse-engineering framework. This tool currently supports TAs of QSEE and Huawei..

More details can be found at static_analysis_tool

2.2 Proof of Concept Exploits

We developed a proof-of-concept arbitrary memory leak (by using physical address) on Qualcomm chipsets and privilege-escalation exploit on Huawei chipsets to verify the hypothesized severity of BOOMERANG.

More details can be found at exploits

2.3 Cooperative Semantic Reconstruction

Due to the limitations of existing BOOMERANG defenses, we propose a novel defense Cooperative Semantic Reconstruction (CSR), which is capable of bridging the semantic gap between the two worlds with minimal modification and minimal overhead. In this defense, the trusted OS and the untrusted OS both cooperate to verify memory pointers that are passed into the secure world to ensure that the untrusted application indeed has permission to access the referenced memory region.

We used OP-TEE to implement and evaluate our defense. More details can be found at: optee

2.4 Papers

All papers and other academic publications based on this can be found under papers.

2.5 Presentations

All the presentations at various venues can be found under presentations

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3. Contact

Issues and Support: boomerang-dev@googlegroups.com

Non-support related: machiry@cs.ucsb.edu

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4. Impact

These vulnerabilities, and our corresponding exploits, affect hundreds of millions of devices that are currently in production today. Our findings have been reported to and verified by the corresponding vendors, who are currently in the process of creating security patches.

CVEs Issued: CVE-2016-5349, CVE-2016-8762, CVE-2016-8763, and CVE-2016-8764

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5. Coming Soon

A patch file with all the modifications we have done to OP-TEE, so that its easy to port our defense to different versions of OP-TEE.