CVE-2006-0807 in Chinese Word Processor
Summary
by MITRE
Stack-based buffer overflow in NJStar Chinese and Japanese Word Processor 4.x and 5.x before 5.10 allows user-assisted attackers to execute arbitrary code via font names in NJStar (.njx) documents.
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Analysis
by VulDB Data Team • 08/02/2017
The vulnerability identified as CVE-2006-0807 represents a critical stack-based buffer overflow flaw within NJStar Chinese and Japanese Word Processor software versions 4.x and 5.x prior to 5.10. This security weakness resides in the document parsing mechanism that processes font information contained within NJStar (.njx) formatted files. The vulnerability specifically manifests when the application encounters font names within these documents, creating an exploitable condition that can be triggered by user-assisted attacks. The flaw stems from inadequate input validation and bounds checking during the processing of font metadata, allowing maliciously crafted font names to overflow the allocated stack buffer and potentially overwrite adjacent memory locations.
The technical implementation of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking permits data to overwrite adjacent stack memory locations. Attackers can exploit this weakness by crafting malicious .njx documents containing overly long font names that exceed the allocated buffer space, typically resulting in stack pointer corruption and potential code execution control flow hijacking. The vulnerability operates under the principle that the application fails to properly validate the length of font name strings before copying them into fixed-size stack buffers, creating an opportunity for attackers to manipulate program execution through carefully constructed input data.
The operational impact of this vulnerability extends beyond simple code execution capabilities, as it provides attackers with a pathway to compromise systems running affected NJStar software versions. The user-assisted nature of the attack means that victims must open a malicious document, which aligns with ATT&CK technique T1204.002 for legitimate user execution. This vulnerability particularly affects environments where users frequently open documents from untrusted sources, making it a significant risk for corporate networks and organizations handling sensitive data. The exploitation could lead to complete system compromise, data theft, or deployment of additional malware payloads through the execution of arbitrary code with the privileges of the affected application.
Mitigation strategies for CVE-2006-0807 primarily focus on updating to NJStar Word Processor version 5.10 or later, which contains patches addressing the buffer overflow condition. Organizations should implement comprehensive software update policies to ensure all affected systems receive timely security patches. Additionally, network administrators should consider implementing application whitelisting controls that restrict execution of untrusted .njx documents and establish strict document handling procedures. The vulnerability also highlights the importance of input validation practices, emphasizing the need for robust bounds checking in all string handling operations. Security teams should monitor for indicators of compromise related to this vulnerability and consider implementing network intrusion detection systems that can identify suspicious document processing activities. Regular security assessments and penetration testing should verify that the patched versions properly address the buffer overflow conditions and that no similar vulnerabilities exist in related software components.