CVE-2019-19555 in fig2dev
Summary
by MITRE
read_textobject in read.c in Xfig fig2dev 3.2.7b has a stack-based buffer overflow because of an incorrect sscanf.
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Analysis
by VulDB Data Team • 03/07/2024
The vulnerability identified as CVE-2019-19555 resides within the Xfig fig2dev tool version 3.2.7b, specifically in the read_textobject function located in the read.c source file. This represents a critical stack-based buffer overflow flaw that arises from improper handling of input data during string parsing operations. The vulnerability manifests when the application processes FIG format files containing specially crafted text objects that trigger an incorrect sscanf function call.
The technical root cause of this vulnerability stems from insufficient bounds checking during the parsing of text data within FIG files. When the read_textobject function executes sscanf to parse text content, it fails to properly validate the length of input data against the allocated buffer size. This allows an attacker to provide input data that exceeds the predetermined buffer limits, resulting in memory corruption that can overwrite adjacent stack memory locations. The flaw directly maps to CWE-121 Stack-based Buffer Overflow, which is classified as a common weakness in software development practices where insufficient bounds checking leads to memory corruption.
The operational impact of this vulnerability extends beyond simple denial of service scenarios. An attacker who successfully exploits this buffer overflow could potentially execute arbitrary code on the target system with the privileges of the user running the fig2dev application. This makes the vulnerability particularly dangerous in environments where the application processes untrusted FIG files from external sources. The attack vector typically involves crafting a malicious FIG file containing oversized text objects that trigger the vulnerable sscanf call when the application attempts to parse the file.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1203 Exploitation for Client Execution, as it represents a method for executing malicious code through the exploitation of software vulnerabilities in document processing applications. The vulnerability affects systems that utilize Xfig for converting FIG format files to various output formats, making it relevant to graphic design environments, documentation systems, and technical illustration workflows. Organizations using fig2dev as part of their automated processing pipelines face significant risk if they do not implement proper input validation measures.
Mitigation strategies for CVE-2019-19555 should prioritize immediate patching of the affected Xfig fig2dev version to the latest available release that contains the necessary buffer overflow fixes. System administrators should also implement input validation measures that restrict the size of text objects within FIG files before processing, and consider deploying sandboxed environments for FIG file processing to limit potential impact from exploitation attempts. Additionally, regular security assessments of document processing applications and enforcement of secure coding practices, particularly around input validation and buffer management, should be implemented to prevent similar vulnerabilities from emerging in the future. The vulnerability demonstrates the critical importance of proper bounds checking in string manipulation operations and serves as a reminder of the security implications of legacy software components that may not adhere to modern secure coding standards.