CVE-2018-19475 in Ghostscript
Summary
by MITRE
psi/zdevice2.c in Artifex Ghostscript before 9.26 allows remote attackers to bypass intended access restrictions because available stack space is not checked when the device remains the same.
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Analysis
by VulDB Data Team • 06/11/2023
The vulnerability identified as CVE-2018-19475 resides within the psi/zdevice2.c component of Artifex Ghostscript software, affecting versions prior to 9.26. This issue represents a critical access control flaw that enables remote attackers to circumvent intended security restrictions through improper stack space validation during device operations. The vulnerability specifically manifests when the device remains unchanged, creating a pathway for unauthorized access that bypasses the system's intended security boundaries.
The technical flaw stems from the absence of stack space verification within the device handling mechanism of Ghostscript's PostScript interpreter. When processing certain device operations, the system fails to validate whether sufficient stack space exists before proceeding with operations that might otherwise be restricted. This oversight creates a condition where malicious actors can exploit the lack of validation to execute operations that should be blocked due to insufficient resources, effectively allowing them to bypass access controls that are normally enforced. The vulnerability operates at the core level of Ghostscript's device management system, making it particularly dangerous as it affects fundamental security mechanisms rather than surface-level features.
The operational impact of this vulnerability extends significantly across multiple threat scenarios and attack vectors. Remote attackers can leverage this flaw to gain unauthorized access to systems processing PostScript or PDF documents through Ghostscript, potentially leading to privilege escalation, data exfiltration, or system compromise. The vulnerability is particularly concerning in environments where Ghostscript is used as a backend processing engine for document handling, print services, or web applications, as it could enable attackers to bypass security controls that protect against malicious document processing. This weakness directly impacts the integrity and confidentiality of systems that rely on Ghostscript for rendering and processing document content, creating opportunities for persistent security breaches.
Mitigation strategies for CVE-2018-19475 focus primarily on immediate software updates and configuration hardening measures. The most effective approach involves upgrading to Ghostscript version 9.26 or later, which includes the necessary stack space validation checks that address the core vulnerability. Organizations should also implement network segmentation and access controls to limit exposure of systems running Ghostscript, particularly those handling untrusted document input. Additionally, administrators should configure input validation mechanisms to restrict document processing parameters and implement monitoring solutions to detect anomalous processing patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-122, which describes buffer overrun conditions, and maps to attack techniques in the ATT&CK framework related to privilege escalation and execution through application-specific vulnerabilities, emphasizing the need for comprehensive security measures beyond simple patching.