CVE-2018-16419 in OpenSC
Summary
by MITRE
Several buffer overflows when handling responses from a Cryptoflex card in read_public_key in tools/cryptoflex-tool.c in OpenSC before 0.19.0-rc1 could be used by attackers able to supply crafted smartcards to cause a denial of service (application crash) or possibly have unspecified other impact.
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Analysis
by VulDB Data Team • 05/06/2023
The vulnerability identified as CVE-2018-16419 represents a critical buffer overflow condition within the OpenSC cryptographic library, specifically affecting the read_public_key function in the cryptoflex-tool.c source file. This flaw exists in OpenSC versions prior to 0.19.0-rc1 and manifests when the application processes responses from Cryptoflex smartcards. The buffer overflow occurs during the parsing of card responses, creating a scenario where malformed or crafted data from a malicious smartcard can trigger unintended memory behavior. The vulnerability falls under the Common Weakness Enumeration category CWE-121, which describes heap-based buffer overflow conditions, and more specifically aligns with CWE-122 for stack-based buffer overflow scenarios. From an attack perspective, this vulnerability maps to the MITRE ATT&CK technique T1059.007 for command and scripting interpreter, as it enables potential remote code execution or denial of service through crafted smartcard inputs.
The technical implementation of this vulnerability stems from inadequate input validation within the smartcard response handling mechanism. When the read_public_key function processes data returned by Cryptoflex cards, it fails to properly bounds-check the incoming data before copying it into fixed-size buffers. This allows an attacker with physical access to a smartcard reader to craft malicious responses that exceed the allocated buffer space, causing memory corruption. The impact extends beyond simple application crashes, as the buffer overflow can potentially be exploited to overwrite adjacent memory locations, leading to arbitrary code execution or system instability. The vulnerability is particularly concerning in environments where smartcard authentication is critical, such as secure token systems, enterprise authentication infrastructure, or government cryptographic applications. The flaw demonstrates poor defensive programming practices and highlights the importance of implementing robust input validation and memory management controls in cryptographic software.
Operational impacts of CVE-2018-16419 are significant across multiple threat scenarios. The primary effect is denial of service, where legitimate users cannot access cryptographic services due to application crashes, potentially disrupting critical authentication processes. However, the vulnerability's potential for more severe consequences cannot be dismissed, as the buffer overflow could enable privilege escalation or remote code execution depending on the system configuration and execution context. In high-security environments, this vulnerability could be exploited to compromise the integrity of cryptographic operations, undermining the security posture of systems relying on OpenSC for smartcard management. The attack vector requires physical proximity to the smartcard reader, but this limitation does not mitigate the risk in environments where attackers have access to the target infrastructure. Organizations using OpenSC for smartcard operations face potential operational disruption, increased maintenance overhead, and potential compliance violations if their systems are compromised through this vulnerability.
Mitigation strategies for CVE-2018-16419 primarily involve upgrading to OpenSC version 0.19.0-rc1 or later, which contains the necessary patches to address the buffer overflow conditions. System administrators should prioritize patch management and ensure all smartcard-based authentication systems are updated promptly. Additional defensive measures include implementing proper input validation at multiple layers of the application stack, deploying intrusion detection systems to monitor for anomalous smartcard communication patterns, and conducting regular security assessments of cryptographic infrastructure. Organizations should also consider implementing network segmentation to limit access to smartcard readers and establish strict access controls for physical security zones. The vulnerability serves as a reminder of the critical importance of secure coding practices, particularly in cryptographic applications where memory safety directly impacts system security. Regular code reviews focusing on buffer management and input validation should be implemented as part of the development lifecycle to prevent similar issues from emerging in future releases. Organizations relying on OpenSC should also monitor for related vulnerabilities in the smartcard ecosystem and maintain updated threat intelligence to protect against evolving attack vectors targeting cryptographic infrastructure.