CVE-2018-16982 in Open Chinese Convert
Summary
by MITRE
Open Chinese Convert (OpenCC) 1.0.5 allows attackers to cause a denial of service (segmentation fault) because BinaryDict::NewFromFile in BinaryDict.cpp may have out-of-bounds keyOffset and valueOffset values via a crafted .ocd file.
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Analysis
by VulDB Data Team • 05/16/2023
Open Chinese Convert version 1.0.5 contains a critical denial of service vulnerability that stems from improper input validation within the BinaryDict::NewFromFile function in BinaryDict.cpp. This vulnerability manifests when processing maliciously crafted .ocd files that contain out-of-bounds keyOffset and valueOffset values, leading to segmentation faults during execution. The flaw represents a classic buffer overflow condition where the application fails to properly validate the offsets within the binary dictionary file structure before attempting to access memory regions. The vulnerability is categorized under CWE-129 as an insufficient input validation issue, specifically involving out-of-bounds access during file parsing operations. Attackers can exploit this weakness by crafting specially formatted .ocd files that contain malformed offset values, causing the application to attempt memory access beyond the allocated boundaries of the dictionary data structure.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be leveraged in broader attack scenarios within systems that utilize OpenCC for text processing or translation services. When exploited, the segmentation fault results in application crashes that can disrupt legitimate user operations and potentially provide attackers with opportunities to execute further malicious activities. The vulnerability affects any system running OpenCC 1.0.5 that processes untrusted .ocd files, making it particularly dangerous in environments where the application handles user-uploaded content or external data sources. Systems utilizing OpenCC for automated translation services, web applications, or content management platforms are especially vulnerable to this type of attack vector.
From an attack perspective, this vulnerability aligns with ATT&CK technique T1499.004 which involves network denial of service attacks, and represents a form of resource exhaustion through application instability. The exploit requires minimal sophistication as it only requires crafting a specific .ocd file with malformed offsets, making it accessible to attackers with basic file manipulation capabilities. Organizations should consider this vulnerability as part of their broader application security posture, particularly in environments where OpenCC is integrated into larger software ecosystems. The vulnerability demonstrates the importance of input validation and proper bounds checking in file parsing operations, which are fundamental security practices that should be implemented across all software components that process external data formats.
Mitigation strategies for CVE-2018-16982 should focus on immediate patching of OpenCC to version 1.1.0 or later, where the vulnerability has been resolved through improved input validation and bounds checking mechanisms. Additionally, organizations should implement strict file validation procedures that verify the integrity of .ocd files before processing, including checksum verification and format validation checks. Network-level defenses such as intrusion detection systems can be configured to monitor for suspicious file upload patterns that might indicate exploitation attempts. The fix implemented in newer versions of OpenCC addresses the root cause by ensuring that all offset values are validated against the actual file boundaries before any memory access operations are performed, thereby preventing the out-of-bounds conditions that lead to segmentation faults. System administrators should also consider implementing application sandboxing or containerization strategies to limit the potential impact of successful exploitation attempts, as this approach can contain the effects of segmentation faults and prevent them from affecting other system components.