CVE-2017-14547 in STDU Viewer
Summary
by MITRE
STDU Viewer 1.6.375 allows attackers to cause a denial of service or possibly have unspecified other impact via a crafted .mobi file, related to a "Read Access Violation starting at STDUMOBIFile!DllUnregisterServer+0x000000000002efc0."
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Analysis
by VulDB Data Team • 11/17/2019
The vulnerability identified as CVE-2017-14547 affects STDU Viewer version 1.6.375, a document viewing application that processes various file formats including the mobi format used for e-books. This issue represents a critical memory corruption flaw that manifests when the application processes maliciously crafted mobi files. The vulnerability stems from improper input validation and memory management within the STDUMOBIFile component, specifically during the DllUnregisterServer function execution. The error condition manifests as a read access violation, indicating that the application attempts to access memory locations that are not properly allocated or accessible, leading to unpredictable behavior.
The technical exploitation of this vulnerability occurs when an attacker crafts a specially formatted .mobi file that triggers memory corruption during the application's processing routine. The specific error location at STDUMOBIFile!DllUnregisterServer+0x000000000002efc0 indicates that the flaw exists within the dynamic link library's unregistration process, suggesting that the vulnerability may be triggered during the cleanup phase of file processing or when the application attempts to properly unload the mobi file handler component. This type of memory access violation falls under the CWE-125 vulnerability category, which encompasses out-of-bounds read errors that can lead to denial of service or arbitrary code execution. The vulnerability's classification aligns with ATT&CK technique T1203, which covers exploitation of memory corruption vulnerabilities for privilege escalation and system compromise.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as the unspecified other impacts could potentially enable remote code execution or system compromise. When an attacker successfully exploits this vulnerability, the application crashes or becomes unresponsive, effectively denying users access to legitimate document viewing functionality. However, the potential for unspecified additional impacts suggests that the memory corruption could be leveraged to execute arbitrary code within the application's context, potentially allowing attackers to gain unauthorized system access. The vulnerability affects users who may inadvertently open maliciously crafted mobi files, making it particularly dangerous in environments where users have limited security awareness or when the application is used in automated processing scenarios.
Mitigation strategies for CVE-2017-14547 should focus on immediate patching of the affected STDU Viewer application to version 1.6.375.1 or later, which contains the necessary memory management fixes and input validation improvements. Organizations should implement strict file validation policies that prevent the automatic processing of untrusted mobi files, particularly in enterprise environments where users may encounter suspicious documents. Network security controls should include content filtering mechanisms that scan for known malicious mobi file patterns and prevent their download or execution. Additionally, users should be educated about the risks of opening documents from untrusted sources and the importance of maintaining updated software versions. System administrators should consider implementing application whitelisting policies that restrict the execution of vulnerable applications until proper patches are deployed. The vulnerability demonstrates the importance of secure coding practices in handling external file formats and the necessity of thorough input validation to prevent memory corruption vulnerabilities that could lead to system compromise.