Attacking and fixing the android protected confirmation protocol

Myrto Arapinis; Vincent Danos; Maïwenn Racouchot; David A. R. Robin; Thomas Zacharias

Attacking and fixing the android protected confirmation protocol

Myrto Arapinis, Vincent Danos, Maïwenn Racouchot, David A. R. Robin, Thomas Zacharias

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Abstract

Android Protected Confirmation (APC) is an authentication protocol designed by Google. It leverages the extra security of the Trusted Execution Environment (TEE) to secure transactions even in the presence of a compromised OS. The intended security guarantee for APC is that if a transaction has been signed under APC, then the user must have previously given its explicit consent, even if an attacker has gained root access to the victim’s Android OS. In this paper, we present a security analysis of APC in the Universal Composability (UC) framework. We uncover two attacks on the design of the protocol which allow a root adversary to issue transactions without the user consenting to them. We provide an attack implementation on a Google Pixel phone, and propose light-weight fixes. Finally, we specify the ideal UC functionality capturing the intended security guarantees for APC, and prove that the fixed protocol UC-realizes it.

Original language	English
Title of host publication	Proceedings of the 10th IEEE European Symposium on Security and Privacy
Publisher	Institute of Electrical and Electronics Engineers
Pages	1-22
Number of pages	22
Publication status	Accepted/In press - 29 Mar 2025
Event	The 10th IEEE European Symposium on Security and Privacy - Ca' Foscari University of Venice, Venice, Italy Duration: 30 Jun 2025 → 4 Jul 2025 Conference number: 10 https://eurosp2025.ieee-security.org/

Publication series

Name	IEEE European Symposium on Security and Privacy
Publisher	Institute of Electrical and Electronics Engineers
ISSN (Print)	2995-1348
ISSN (Electronic)	2995-1356

Symposium

Symposium	The 10th IEEE European Symposium on Security and Privacy
Abbreviated title	EuroS&P 2025
Country/Territory	Italy
City	Venice
Period	30/06/25 → 4/07/25
Internet address	https://eurosp2025.ieee-security.org/

Keywords / Materials (for Non-textual outputs)

trusted execution environments
android
authentication
universal composability

Access to Document

ArapinisEtalEuroS&P2025AttackingandFixingtheAndroidAccepted author manuscript, 0.99 MBLicence: Creative Commons: Attribution (CC-BY)

Hardware Security Module For Secure Delegated Quantum Cloud Computing
Arapinis, M. (Principal Investigator) & Doosti, M. (Co-investigator)
Engineering and Physical Sciences Research Council
1/07/24 → 30/06/27
Project: Research

Cite this

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title = "Attacking and fixing the android protected confirmation protocol",

abstract = "Android Protected Confirmation (APC) is an authentication protocol designed by Google. It leverages the extra security of the Trusted Execution Environment (TEE) to secure transactions even in the presence of a compromised OS. The intended security guarantee for APC is that if a transaction has been signed under APC, then the user must have previously given its explicit consent, even if an attacker has gained root access to the victim{\textquoteright}s Android OS. In this paper, we present a security analysis of APC in the Universal Composability (UC) framework. We uncover two attacks on the design of the protocol which allow a root adversary to issue transactions without the user consenting to them. We provide an attack implementation on a Google Pixel phone, and propose light-weight fixes. Finally, we specify the ideal UC functionality capturing the intended security guarantees for APC, and prove that the fixed protocol UC-realizes it.",

keywords = "trusted execution environments, android, authentication, universal composability",

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month = mar,

day = "29",

language = "English",

series = "IEEE European Symposium on Security and Privacy",

publisher = "Institute of Electrical and Electronics Engineers",

pages = "1--22",

booktitle = "Proceedings of the 10th IEEE European Symposium on Security and Privacy",

address = "United States",

note = "The 10th IEEE European Symposium on Security and Privacy, EuroS&P 2025 ; Conference date: 30-06-2025 Through 04-07-2025",

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Arapinis, M, Danos, V, Racouchot, M, Robin, DAR & Zacharias, T 2025, Attacking and fixing the android protected confirmation protocol. in Proceedings of the 10th IEEE European Symposium on Security and Privacy. IEEE European Symposium on Security and Privacy, Institute of Electrical and Electronics Engineers, pp. 1-22, The 10th IEEE European Symposium on Security and Privacy, Venice, Italy, 30/06/25.

Attacking and fixing the android protected confirmation protocol. / Arapinis, Myrto; Danos, Vincent; Racouchot, Maïwenn et al.
Proceedings of the 10th IEEE European Symposium on Security and Privacy. Institute of Electrical and Electronics Engineers, 2025. p. 1-22 (IEEE European Symposium on Security and Privacy).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

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T1 - Attacking and fixing the android protected confirmation protocol

AU - Arapinis, Myrto

AU - Danos, Vincent

AU - Racouchot, Maïwenn

AU - Robin, David A. R.

AU - Zacharias, Thomas

N1 - Conference code: 10

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Y1 - 2025/3/29

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AB - Android Protected Confirmation (APC) is an authentication protocol designed by Google. It leverages the extra security of the Trusted Execution Environment (TEE) to secure transactions even in the presence of a compromised OS. The intended security guarantee for APC is that if a transaction has been signed under APC, then the user must have previously given its explicit consent, even if an attacker has gained root access to the victim’s Android OS. In this paper, we present a security analysis of APC in the Universal Composability (UC) framework. We uncover two attacks on the design of the protocol which allow a root adversary to issue transactions without the user consenting to them. We provide an attack implementation on a Google Pixel phone, and propose light-weight fixes. Finally, we specify the ideal UC functionality capturing the intended security guarantees for APC, and prove that the fixed protocol UC-realizes it.

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KW - authentication

KW - universal composability

M3 - Conference contribution

T3 - IEEE European Symposium on Security and Privacy

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BT - Proceedings of the 10th IEEE European Symposium on Security and Privacy

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T2 - The 10th IEEE European Symposium on Security and Privacy

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ER -

Attacking and fixing the android protected confirmation protocol

Abstract

Publication series

Symposium

Keywords / Materials (for Non-textual outputs)

Access to Document

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Projects

Hardware Security Module For Secure Delegated Quantum Cloud Computing

Cite this