CVE-2017-9618 in Ghostscript GhostXPS
Summary
by MITRE
The xps_load_sfnt_name function in xps/xpsfont.c in Artifex Ghostscript GhostXPS 9.22 allows remote attackers to cause a denial of service (buffer overflow and application crash) or possibly have unspecified other impact via a crafted document.
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Analysis
by VulDB Data Team • 12/14/2022
The vulnerability identified as CVE-2017-9618 represents a critical buffer overflow flaw within the GhostXPS component of Artifex Ghostscript version 9.22. This issue resides in the xps_load_sfnt_name function located in the xps/xpsfont.c source file, where improper input validation leads to memory corruption during processing of XPS documents. The vulnerability affects the broader Ghostscript ecosystem and specifically targets the XPS document handling capabilities that are essential for rendering print jobs and document conversions in enterprise environments.
The technical exploitation of this vulnerability occurs when a maliciously crafted XPS document is processed by the affected Ghostscript version. The xps_load_sfnt_name function fails to properly validate the length of font name data within the XPS document structure, allowing an attacker to supply oversized or malformed font name entries that exceed allocated buffer boundaries. This buffer overflow condition results in memory corruption that manifests as application crashes or potential arbitrary code execution depending on the execution environment and memory layout. The flaw demonstrates characteristics consistent with CWE-121, which describes stack-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for execution through scripting languages or document processing.
From an operational perspective, this vulnerability presents significant risk to organizations relying on Ghostscript for document processing, print management, or PDF conversion services. Attackers can leverage this flaw to perform denial of service attacks against systems processing XPS documents, potentially disrupting critical business operations or creating opportunities for more sophisticated attacks. The remote nature of the vulnerability means that attackers can exploit it through web-based interfaces, email attachments, or file sharing systems without requiring local access. Organizations with extensive print server deployments or document processing pipelines are particularly vulnerable, as these systems often process untrusted documents from multiple sources.
Mitigation strategies for CVE-2017-9618 should prioritize immediate patching of affected Ghostscript installations to version 9.23 or later, which contains the necessary fixes for the buffer overflow condition. Network segmentation and input validation measures can provide additional defense layers by filtering suspicious XPS documents before they reach processing systems. Implementing sandboxing techniques for document handling and restricting file type processing capabilities can further reduce the attack surface. Organizations should also monitor for exploitation attempts through log analysis and implement intrusion detection systems that can identify patterns consistent with XPS document processing attacks. The vulnerability highlights the importance of regular security updates and proper input validation in document processing software, particularly in environments where untrusted content is regularly processed.