CVE-2017-14543 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 .epub file, related to "Data from Faulting Address controls Branch Selection starting at STDUEPubFile!DllUnregisterServer+0x0000000000039335."
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Analysis
by VulDB Data Team • 11/17/2019
The vulnerability identified as CVE-2017-14543 affects STDU Viewer version 1.6.375, a document viewer application designed for reading various file formats including epub publications. This issue represents a critical security flaw that stems from improper handling of malformed input data within the application's epub file processing pipeline. The vulnerability manifests when the software encounters a specially crafted .epub file that contains malformed data structures, specifically targeting the STDUEPubFile component responsible for epub file operations. The flaw exists in the DllUnregisterServer function within the STDUEPubFile module, where the application fails to properly validate input data from faulting addresses before using this data to control branch selection logic during program execution.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where programs access memory locations beyond the bounds of allocated buffers. Additionally, this issue demonstrates characteristics of CWE-248, indicating an exception handling flaw where an unhandled exception leads to program termination and potential system instability. The vulnerability operates through a classic buffer overflow scenario where attacker-controlled data from a malicious epub file influences the program's control flow, potentially allowing for arbitrary code execution or complete application crash. The faulting address mentioned in the vulnerability description specifically points to the STDUEPubFile!DllUnregisterServer+0x000000000000039335 location, indicating that the memory corruption occurs during the dynamic link library's cleanup process when attempting to unregister components.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it can potentially enable more sophisticated attacks depending on the execution environment and system configuration. When exploited, the vulnerability can cause the STDU Viewer application to crash or become unresponsive, effectively rendering the application unusable for legitimate users. However, the unspecified other impacts mentioned in the description suggest that under certain conditions, this flaw might provide opportunities for privilege escalation or code execution within the application's security context. The vulnerability is particularly concerning because it requires no special privileges to exploit, making it accessible to any attacker who can convince a user to open a malicious epub file. This characteristic places the vulnerability in the ATT&CK framework under the T1203 - Exploitation for Client Execution tactic, where adversaries leverage application vulnerabilities to execute malicious code.
Mitigation strategies for CVE-2017-14543 should prioritize immediate application updates from the vendor to address the underlying buffer overflow condition in the epub processing module. System administrators should implement application whitelisting policies to restrict execution of untrusted epub files, particularly in enterprise environments where users may encounter potentially malicious content. Network-based defenses should include content filtering mechanisms that scan epub files for known malicious patterns or structures that could trigger the vulnerability. Organizations should also consider implementing sandboxing techniques for epub file processing to isolate potential exploitation attempts from the core operating system. The vulnerability highlights the importance of proper input validation and memory management practices, emphasizing that applications should never trust external input data without thorough sanitization and validation before processing. Security monitoring should include detection of unusual application crash patterns or unexpected behavior when processing epub files, as these could indicate exploitation attempts. Additionally, users should be educated about the risks of opening epub files from untrusted sources, and organizations should establish clear policies regarding the handling and validation of external document formats to prevent exploitation of similar vulnerabilities in the future.