CVE-2023-4535 in OpenSC
Summary
by MITRE • 11/06/2023
An out-of-bounds read vulnerability was found in OpenSC packages within the MyEID driver when handling symmetric key encryption. Exploiting this flaw requires an attacker to have physical access to the computer and a specially crafted USB device or smart card. This flaw allows the attacker to manipulate APDU responses and potentially gain unauthorized access to sensitive data, compromising the system's security.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 07/26/2025
The vulnerability identified as CVE-2023-4535 represents a critical out-of-bounds read flaw within the OpenSC framework's MyEID driver implementation. This security weakness specifically manifests during symmetric key encryption operations, where the system fails to properly validate input parameters before processing them. The flaw exists in the APDU (Application Protocol Data Unit) handling mechanism, which serves as the communication protocol between smart card readers and the underlying cryptographic software. The vulnerability is classified under CWE-125 as an out-of-bounds read, indicating that the software accesses memory locations beyond the allocated buffer boundaries, potentially exposing sensitive information or causing system instability.
The exploitation of this vulnerability requires specific prerequisites that limit its attack surface but do not eliminate the risk entirely. An attacker must possess physical access to the target system and be able to introduce a malicious USB device or smart card that can trigger the flawed code path. This physical access requirement aligns with ATT&CK technique T1550.001 for use of valid accounts and T1059.001 for command and script interpreter, as the attacker would need to interact directly with the system to establish the malicious hardware presence. The attack vector typically involves crafting a specially designed smart card or USB device that, when inserted into the system, triggers the vulnerable code path during normal cryptographic operations.
The operational impact of CVE-2023-4535 extends beyond simple data exposure, as it provides attackers with the capability to manipulate APDU responses in ways that can compromise the entire cryptographic infrastructure. When the system processes the malformed input, it can read memory locations containing sensitive data such as cryptographic keys, authentication tokens, or personal identification information. This manipulation capability allows for potential privilege escalation within the cryptographic context, enabling unauthorized access to protected data that should remain secure. The vulnerability essentially undermines the trust model that smart card systems rely upon, as it allows attackers to bypass normal security boundaries that should protect sensitive cryptographic operations.
Mitigation strategies for this vulnerability should focus on both immediate remediation and long-term architectural improvements. System administrators should prioritize updating to patched versions of OpenSC that address the out-of-bounds read condition, ensuring that all MyEID driver implementations are current with security patches. Organizations should implement strict physical security measures to prevent unauthorized hardware insertion, including disabling unused USB ports and implementing hardware-based security controls. The security community should also consider adopting additional input validation measures within the APDU processing framework to prevent similar vulnerabilities from emerging in other cryptographic implementations. Furthermore, regular security assessments of smart card infrastructure and continuous monitoring of system logs for anomalous APDU behavior can help detect potential exploitation attempts before they succeed.