CVE-2018-7546 in WPS Office
Summary
by MITRE
wpsmain.dll in Kingsoft WPS Office 2016 and Jinshan PDF 10.1.0.6621 allows remote attackers to cause a denial of service via a crafted pdf file.
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Analysis
by VulDB Data Team • 03/08/2020
The vulnerability identified as CVE-2018-7546 resides within the wpsmain.dll component of Kingsoft WPS Office 2016 and Jinshan PDF 10.1.0.6621 software suites, representing a critical denial of service weakness that can be exploited through maliciously crafted pdf files. This flaw specifically targets the processing engine responsible for handling pdf documents within these office applications, creating a pathway for remote attackers to disrupt normal operations without requiring local system access or authentication. The vulnerability demonstrates characteristics consistent with improper input validation and memory handling issues that fall under the broader category of software robustness failures.
The technical exploitation mechanism involves the careful construction of pdf files that trigger buffer overflows or memory corruption conditions within the wpsmain.dll library when these documents are opened or processed by the affected applications. When a victim opens the malicious pdf file, the vulnerable code path in the pdf rendering engine executes with malformed input data that exceeds expected buffer boundaries or violates memory access constraints. This results in application crashes, process termination, or system instability that effectively denies service to legitimate users attempting to access or work with pdf documents. The flaw represents a classic example of a buffer overflow vulnerability that can be categorized under CWE-121 as heap-based buffer overflow conditions or potentially CWE-125 for out-of-bounds read conditions.
From an operational perspective, this vulnerability creates significant risk for organizations relying on WPS Office and Jinshan PDF applications, as it enables remote attackers to disrupt business operations through simple pdf file delivery methods. Attackers can leverage this weakness to perform persistent denial of service attacks against targeted users or systems, potentially causing productivity losses and operational disruptions in enterprise environments where these applications are widely deployed. The remote nature of the attack means that victims need not be physically present or have direct system access for exploitation to occur, making the vulnerability particularly dangerous in networked environments where pdf files are commonly shared through email, web downloads, or file transfer protocols. This characteristic aligns with ATT&CK technique T1499.004 for network denial of service attacks through application-level vulnerabilities.
Organizations should implement immediate mitigations including restricting pdf file downloads from untrusted sources, deploying application whitelisting policies to prevent execution of vulnerable applications, and ensuring timely patch updates from Kingsoft or alternative office suites. System administrators should consider disabling pdf viewing capabilities within web browsers or office applications until proper security patches are applied, and network monitoring should be enhanced to detect unusual pdf file access patterns or application crashes that may indicate exploitation attempts. The vulnerability highlights the importance of regular software updates and security assessments for office productivity suites, particularly those handling complex document formats like pdf files that require extensive parsing and rendering capabilities. Organizations should also consider transitioning to more robust and regularly patched office suites that maintain better security track records and provide more comprehensive vulnerability management processes to prevent similar issues from affecting their operational environments.