CVE-2017-1000413 in OP-TEE
Summary
by MITRE
Linaro's open source TEE solution called OP-TEE, version 2.4.0 (and older) is vulnerable a timing attack in the Montgomery parts of libMPA in OP-TEE resulting in a compromised private RSA key.
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Analysis
by VulDB Data Team • 01/19/2023
The vulnerability identified as CVE-2017-1000413 affects OP-TEE, an open source Trusted Execution Environment solution developed by Linaro. This security flaw exists in version 2.4.0 and all earlier releases of the OP-TEE framework. The vulnerability specifically targets the Montgomery multiplication algorithms implemented within the libMPA library component of OP-TEE. These algorithms are fundamental cryptographic operations used in RSA key generation and encryption processes. The flaw represents a significant weakness in the cryptographic implementation that could potentially compromise the security of RSA private keys stored within the secure environment. The vulnerability arises from the implementation of timing-dependent operations that do not adequately mask the execution time variations inherent in cryptographic computations.
The technical root cause of this vulnerability lies in the timing attack resistance mechanisms within the Montgomery multiplication routines of libMPA. When performing cryptographic operations such as RSA key generation or signature verification, the Montgomery multiplication algorithm exhibits timing variations that correlate with the secret data being processed. These timing variations occur because the algorithm's execution time depends on the bit patterns of the operands, particularly during the modular reduction phase of the computation. Attackers can exploit these timing differences through statistical analysis of execution time measurements to reconstruct the secret RSA private key components. This vulnerability directly maps to CWE-320: "Cryptographic Issues" and specifically addresses weaknesses in key management and cryptographic implementation. The attack vector requires the adversary to have access to the target system and the ability to measure execution time variations with sufficient precision to extract meaningful information about the secret key.
The operational impact of this vulnerability extends beyond simple cryptographic compromise, as it undermines the fundamental security guarantees provided by the Trusted Execution Environment. When an attacker successfully extracts the RSA private key through timing attacks, they gain the ability to forge digital signatures, decrypt sensitive communications, and impersonate legitimate entities within the secure environment. This compromise affects any cryptographic operations relying on RSA keys generated or stored within OP-TEE, including secure boot processes, authentication mechanisms, and secure communication protocols. The vulnerability particularly impacts systems where OP-TEE is used for secure key storage and cryptographic operations, such as mobile devices, IoT systems, and embedded platforms that depend on hardware security modules for cryptographic services. The attack can be executed remotely in certain scenarios, making it a significant concern for deployed systems that have not been patched.
Mitigation strategies for this vulnerability involve multiple layers of protection and system updates. The primary recommendation is to upgrade to OP-TEE version 2.5.0 or later, which includes fixed implementations of the Montgomery multiplication algorithms with proper timing attack resistance mechanisms. Organizations should also implement constant-time algorithm implementations that eliminate timing variations regardless of input data patterns. Additional protective measures include deploying hardware-based countermeasures such as hardware random number generators and ensuring proper physical security controls to limit access to systems with vulnerable implementations. The remediation process should also include comprehensive security testing of cryptographic implementations and regular vulnerability assessments to identify similar timing attack vulnerabilities in other cryptographic libraries. System administrators should monitor for any signs of attempted exploitation and maintain updated threat intelligence regarding timing attack techniques targeting cryptographic implementations. This vulnerability highlights the importance of adhering to established security frameworks such as NIST SP 800-38B for cryptographic algorithm implementations and following ATT&CK technique T1059.001 for understanding how timing attacks can be leveraged to compromise cryptographic systems.