CVE-2017-6953 in SmartDiag Diagnosis Tool
Summary
by MITRE
Gemalto SmartDiag Diagnosis Tool v2.5 has a stack-based Buffer Overflow with SEH Overwrite via long "Register a new card" input fields. There may be a risk of local code execution with untrusted input to SmartDiag.exe or SymDiag.exe.
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Analysis
by VulDB Data Team • 09/24/2020
The vulnerability identified as CVE-2017-6953 affects Gemalto SmartDiag Diagnosis Tool version 2.5, representing a critical stack-based buffer overflow condition that specifically targets the software's handling of user input during card registration processes. This flaw manifests when attackers provide excessively long input data to the "Register a new card" functionality, creating a scenario where the application fails to properly validate input length before writing to allocated memory buffers. The buffer overflow occurs in the context of the SmartDiag.exe or SymDiag.exe executables, which are core components of the Gemalto diagnostic tool suite used for managing smart card operations and system diagnostics. The vulnerability is particularly concerning because it enables exploitation through structured exception handling (SEH) overwrite techniques, which provide attackers with sophisticated control over the program execution flow.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the application's user interface handling code, specifically in how it processes card registration data. When the application receives input exceeding the allocated buffer size, the excess data overflows into adjacent memory locations, potentially corrupting the stack structure and overwriting the structured exception handler chain. This SEH overwrite capability allows attackers to redirect program execution to malicious code injected into the memory space, effectively bypassing standard security protections and creating a persistent code execution vector. The vulnerability is classified as a stack-based buffer overflow under CWE-121, which specifically addresses conditions where insufficient bounds checking allows data to be written beyond the boundaries of allocated stack memory, and it aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution through Windows command shell manipulation.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it presents a significant local code execution risk that could be exploited by attackers with physical access to systems or those already operating within the target environment. Attackers leveraging this vulnerability could potentially install malware, escalate privileges, or establish persistent backdoors within systems running the affected Gemalto software. The attack surface is particularly concerning given that SmartDiag tools are often deployed in enterprise environments for critical infrastructure management, making successful exploitation potentially devastating for organizations relying on smart card-based authentication systems. The vulnerability's exploitation requires minimal privileges and can be executed through simple input manipulation, making it particularly dangerous in environments where users may have elevated access rights to the diagnostic tools.
Mitigation strategies for CVE-2017-6953 should prioritize immediate software updates from Gemalto to address the identified buffer overflow conditions and implement robust input validation measures. Organizations should disable or restrict access to the vulnerable SmartDiag.exe and SymDiag.exe executables until patches are deployed, particularly in environments where untrusted users might interact with the diagnostic tools. Network segmentation and privilege separation can help limit the potential impact if exploitation occurs, while application whitelisting policies should be implemented to prevent unauthorized execution of patched or vulnerable versions. Security monitoring should focus on detecting anomalous execution patterns or unexpected process creation events that might indicate exploitation attempts, and regular vulnerability assessments should be conducted to identify similar buffer overflow conditions in other legacy applications. The remediation process should also include comprehensive testing of patched versions to ensure that the buffer overflow protections do not introduce compatibility issues with legitimate card registration operations, as the attack vector specifically targets the registration functionality that is core to the software's intended use case.