CVE-2017-1000187 in SWFTools
Summary
by MITRE
In SWFTools, an address access exception was found in pdf2swf. FoFiTrueType::writeTTF()
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Analysis
by VulDB Data Team • 01/10/2023
The vulnerability CVE-2017-1000187 represents a critical memory access issue within SWFTools, specifically in the pdf2swf utility component. This flaw manifests in the FoFiTrueType::writeTTF() function which handles TrueType font processing during PDF to SWF conversion operations. The vulnerability arises from improper bounds checking and memory management during font data processing, creating a potential avenue for arbitrary code execution or system compromise. SWFTools is widely used for converting various document formats to Adobe Flash format, making this vulnerability particularly concerning for environments where document conversion services are prevalent.
The technical implementation of this vulnerability stems from insufficient validation of font data structures within the FoFiTrueType class. When pdf2swf processes PDF documents containing specially crafted TrueType font data, the writeTTF() function fails to properly validate array indices and buffer boundaries before accessing memory locations. This results in an address access exception that can be exploited to trigger memory corruption, potentially allowing attackers to execute malicious code with the privileges of the affected application. The vulnerability is classified as a buffer overflow condition under CWE-121, specifically involving stack-based buffer overflow scenarios where insufficient bounds checking leads to memory corruption. The flaw demonstrates characteristics of CWE-787, which deals with out-of-bounds writes, and CWE-125, concerning out-of-bounds read conditions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it can potentially enable remote code execution when SWFTools is used in web applications or automated processing environments. Attackers can craft malicious PDF documents containing malformed font data that, when processed by pdf2swf, will trigger the memory access exception. This creates a significant risk for organizations that rely on SWFTools for document conversion services, particularly those exposed to untrusted input from external sources. The vulnerability affects systems where SWFTools is installed and actively used for PDF to SWF conversion, including content management systems, document processing pipelines, and web applications that utilize this toolchain. The ATT&CK framework categorizes this vulnerability under T1059 for command and scripting interpreter and T1203 for Exploitation for Client Execution, as it enables attackers to execute arbitrary code through compromised conversion processes.
Mitigation strategies for CVE-2017-1000187 require immediate patching of SWFTools installations to address the underlying memory access issues in the FoFiTrueType::writeTTF() function. Organizations should implement strict input validation and sanitization measures when processing PDF documents through SWFTools, particularly by rejecting documents containing suspicious font data or implementing sandboxing mechanisms around the conversion process. Network segmentation and access controls should be enforced to limit exposure of SWFTools to untrusted inputs, while regular security audits should monitor for unauthorized installations or usage of vulnerable versions. Additionally, organizations should consider implementing alternative document conversion methods that do not rely on vulnerable components, and maintain comprehensive monitoring for suspicious activities related to document processing operations. The vulnerability demonstrates the importance of proper memory management and bounds checking in security-critical applications, particularly those handling untrusted data from external sources.