CVE-2010-4531 in PCSC-Lite
Summary
by MITRE
Stack-based buffer overflow in the ATRDecodeAtr function in the Answer-to-Reset (ATR) Handler (atrhandler.c) for pcscd in PCSC-Lite 1.5.3, and possibly other 1.5.x and 1.6.x versions, allows physically proximate attackers to cause a denial of service (crash) and possibly execute arbitrary code via a smart card with an ATR message containing a long attribute value.
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Analysis
by VulDB Data Team • 10/12/2021
The vulnerability identified as CVE-2010-4531 represents a critical stack-based buffer overflow within the PCSC-Lite smart card daemon implementation. This flaw exists in the ATRDecodeAtr function located in the atrhandler.c file, which processes Answer-to-Reset (ATR) messages from smart cards. The issue affects PCSC-Lite version 1.5.3 and potentially other versions within the 1.5.x and 1.6.x release lines, making it a widespread concern for smart card communication systems. The vulnerability is particularly concerning because it can be exploited by attackers who are physically proximate to the target system, meaning the attack requires only local access to the smart card reader rather than remote network connectivity.
The technical nature of this vulnerability stems from inadequate bounds checking within the ATR decoding process. When a smart card presents an ATR message containing an unusually long attribute value, the ATRDecodeAtr function fails to validate the length of incoming data before copying it into a fixed-size stack buffer. This classic buffer overflow condition occurs because the function assumes that attribute values will not exceed predetermined limits, but maliciously crafted ATR messages can exceed these boundaries. The overflow allows attackers to overwrite adjacent stack memory, potentially corrupting program execution flow and creating opportunities for arbitrary code execution. According to CWE-121, this represents a classic stack-based buffer overflow vulnerability where insufficient bounds checking leads to memory corruption. The attack vector is classified as local proximity, aligning with ATT&CK technique T1059.007 for command and scripting interpreter execution, as the overflow can potentially enable code execution through memory corruption.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable complete system compromise. A successful exploitation can cause the pcscd daemon to crash, resulting in smart card communication failures and service disruption. However, the more serious concern lies in the potential for arbitrary code execution, which could allow attackers to gain elevated privileges on the affected system. Since pcscd typically runs with elevated privileges to access hardware smart card readers, successful exploitation could provide attackers with direct access to smart card communication channels and potentially enable further attacks against the system. The vulnerability affects systems where smart card readers are present and where PCSC-Lite is installed, including enterprise environments, government systems, and any infrastructure relying on smart card authentication. This makes it particularly dangerous in contexts where smart card-based authentication is used for access control, digital signatures, or secure communications.
Mitigation strategies for CVE-2010-4531 should focus on immediate patching of affected systems, as this vulnerability has been addressed in subsequent PCSC-Lite releases. Organizations should prioritize updating to PCSC-Lite versions that contain fixed implementations of the ATR decoding functions, ensuring proper bounds checking and input validation. System administrators should also implement monitoring for abnormal pcscd behavior and consider network segmentation to limit physical access to smart card readers where possible. Additional protective measures include disabling unnecessary smart card services, implementing proper access controls for smart card readers, and conducting regular security assessments of smart card infrastructure. The vulnerability highlights the importance of input validation in security-critical systems and serves as a reminder that hardware interaction components, particularly those handling untrusted data from external devices, require robust security controls. Organizations should also consider implementing intrusion detection systems that can identify potential exploitation attempts and establish incident response procedures for smart card-related security incidents. Given the nature of the vulnerability and its potential for privilege escalation, comprehensive security audits of smart card infrastructure should be conducted to identify and remediate similar issues throughout the system.