CVE-2018-19492 in Gnuplot
Summary
by MITRE
An issue was discovered in cairo.trm in Gnuplot 5.2.5. This issue allows an attacker to conduct a buffer overflow with an arbitrary amount of data in the cairotrm_options function. This flaw is caused by a missing size check of an argument passed to the "set font" function. This issue occurs when the Gnuplot pngcairo terminal is used as a backend.
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Analysis
by VulDB Data Team • 06/11/2023
The vulnerability identified as CVE-2018-19492 represents a critical buffer overflow flaw within the Gnuplot 5.2.5 software implementation, specifically affecting the cairo.trm terminal functionality. This issue manifests when the pngcairo terminal is utilized as a backend rendering engine, creating a dangerous condition where attacker-controlled data can be processed without proper size validation. The flaw exists within the cairotrm_options function where insufficient input sanitization allows for arbitrary data overflow scenarios.
The technical root cause stems from a missing size check mechanism within the argument handling process of the "set font" function. When users or applications invoke the pngcairo terminal with specific font parameters, the system fails to validate the length of incoming data before processing it through the cairotrm_options function. This absence of boundary checking creates a predictable overflow condition where maliciously crafted input can overwrite adjacent memory regions, potentially leading to arbitrary code execution or application crashes. The vulnerability operates under CWE-121, which categorizes buffer overflow conditions where insufficient bounds checking allows memory access beyond allocated buffers, and more specifically aligns with CWE-787, which addresses out-of-bounds writes that occur when a buffer is accessed beyond its boundaries.
The operational impact of this vulnerability extends beyond simple denial-of-service scenarios, as it presents a significant attack surface for privilege escalation and remote code execution. An attacker who can influence the gnuplot command execution or provide crafted input to a vulnerable system could potentially leverage this flaw to execute arbitrary commands with the privileges of the gnuplot process. The vulnerability is particularly concerning in environments where gnuplot is used as a backend service or processing untrusted data inputs, as it could be exploited through web applications or automated systems that utilize gnuplot for chart generation. This flaw directly correlates with ATT&CK technique T1203, which involves exploiting vulnerabilities in applications to gain code execution capabilities, and T1059, which covers command and scripting interpreter usage for exploitation.
Mitigation strategies for CVE-2018-19492 should prioritize immediate patch application from the Gnuplot maintainers, as this vulnerability affects the core rendering functionality of the software. Organizations should implement input validation measures at the application level to sanitize all font-related parameters before they reach the cairo terminal processing functions. Additionally, system administrators should consider restricting gnuplot execution privileges and implementing network segmentation to limit potential attack vectors. The vulnerability demonstrates the importance of proper bounds checking and input validation in graphics rendering libraries, as similar issues could exist in other terminal implementations within the gnuplot ecosystem. Regular security audits of third-party libraries and terminal plugins should be conducted to identify and remediate similar buffer overflow vulnerabilities that could compromise system integrity and availability.