CVE-2013-3934 in Writer 2012
Summary
by MITRE
Stack-based buffer overflow in Kingsoft Writer 2012 8.1.0.3030, as used in Kingsoft Office 2013 before 9.1.0.4256, allows remote attackers to execute arbitrary code via a long font name in a WPS file.
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Analysis
by VulDB Data Team • 12/25/2024
The vulnerability identified as CVE-2013-3934 represents a critical stack-based buffer overflow flaw discovered in Kingsoft Writer 2012 version 8.1.0.3030, which was subsequently integrated into Kingsoft Office 2013 prior to version 9.1.0.4256. This vulnerability manifests when the affected software processes WPS files containing excessively long font names, creating a condition where memory allocation fails to properly validate input lengths. The flaw falls under CWE-121 Stack-based Buffer Overflow, a well-documented weakness in software security that occurs when data written to a stack buffer exceeds the buffer's allocated size, potentially overwriting adjacent memory locations. The vulnerability is particularly concerning as it enables remote code execution, making it a prime target for attackers seeking to compromise systems through malicious file delivery mechanisms.
The technical exploitation of this vulnerability occurs when a maliciously crafted WPS file is opened by an affected version of Kingsoft Writer or Kingsoft Office. The software's parser fails to properly validate the length of font names within the WPS file format, allowing an attacker to supply a font name that exceeds the allocated buffer space on the stack. When the application attempts to process this oversized font name, it overflows the buffer and potentially overwrites critical memory locations including return addresses, function pointers, or other control data. This memory corruption can be leveraged by attackers to redirect program execution flow and inject malicious code, effectively achieving remote code execution without requiring local system access. The vulnerability's remote exploitability stems from the fact that WPS files can be delivered through various attack vectors including email attachments, web downloads, or malicious websites.
The operational impact of CVE-2013-3934 extends beyond simple code execution, as it provides attackers with a pathway to establish persistent access to compromised systems. The vulnerability affects a widely used office suite that was prevalent in enterprise and consumer environments, making it a significant threat vector for targeted attacks. Organizations running affected versions of Kingsoft Office were particularly vulnerable to phishing campaigns where attackers could deliver malicious WPS files that would automatically execute upon opening, bypassing traditional security measures that might not detect such attacks. The vulnerability's exploitation could result in complete system compromise, data exfiltration, and the installation of backdoors or additional malware. Security researchers noted that the attack surface was particularly wide given the popularity of Kingsoft Office in various regions, especially in Asia, where the software enjoyed significant market share.
Mitigation strategies for CVE-2013-3934 primarily focus on immediate software updates and operational security measures. The most effective remediation involves upgrading to Kingsoft Office 2013 version 9.1.0.4256 or later, which contains the necessary patches to address the buffer overflow vulnerability. Organizations should implement comprehensive patch management policies to ensure all instances of the affected software are updated promptly. Additional defensive measures include deploying email filtering solutions that can identify and block WPS files from untrusted sources, implementing application whitelisting policies that restrict execution of unverified office applications, and conducting regular security assessments to identify potentially vulnerable systems. From an ATT&CK framework perspective, this vulnerability maps to techniques involving initial access through malicious files and privilege escalation through code execution, making it a critical component in threat hunting and incident response activities. Network segmentation and monitoring for unusual file opening patterns can help detect exploitation attempts, while user education regarding suspicious file attachments remains essential in preventing successful attacks.