CVE-2019-5087 in xcftools
Summary
by MITRE
An exploitable integer overflow vulnerability exists in the flattenIncrementally function in the xcf2png and xcf2pnm binaries of xcftools 1.0.7. An integer overflow can occur while calculating the row's allocation size, that could be exploited to corrupt memory and eventually execute arbitrary code. In order to trigger this vulnerability, a victim would need to open a specially crafted XCF file.
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Analysis
by VulDB Data Team • 02/26/2024
The vulnerability described in CVE-2019-5087 represents a critical integer overflow flaw within the xcftools 1.0.7 suite, specifically affecting the flattenIncrementally function in xcf2png and xcf2pnm utilities. This issue stems from improper handling of memory allocation calculations during image processing operations, creating a pathway for malicious code execution through crafted input files. The vulnerability is particularly concerning as it resides in image conversion tools that are commonly used for processing graphics files, making it accessible through routine file operations that users might encounter in daily workflows. The integer overflow occurs when calculating the memory allocation size for image rows, where mathematical operations exceed the maximum representable value for the integer type being used, leading to unexpected behavior in memory management.
The technical exploitation of this vulnerability requires a victim to open a specially crafted XCF (eXperimental Color Format) file that triggers the overflow condition within the flattenIncrementally function. When processing such malicious files, the integer overflow corrupts memory allocation calculations, potentially leading to buffer overflows or other memory corruption issues that can be leveraged by attackers to execute arbitrary code with the privileges of the affected application. The flaw demonstrates a classic software security weakness where input validation and boundary checking are insufficient, allowing attackers to manipulate integer values in ways that bypass normal safety mechanisms. This vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and represents a direct threat to the integrity of the application's memory management system.
The operational impact of this vulnerability extends beyond simple code execution, as it affects the fundamental security posture of systems that process XCF files through the affected tools. Attackers could potentially craft malicious XCF files that, when opened by unsuspecting users, would trigger the overflow and provide remote code execution capabilities. This makes the vulnerability particularly dangerous in environments where users frequently open files from untrusted sources or when these tools are used in automated processing pipelines. The attack surface is broadened by the fact that XCF files are commonly used in graphic design workflows, making the exploitation vector highly accessible to various threat actors. Additionally, the vulnerability's presence in widely-used image processing utilities means that successful exploitation could affect multiple systems across different platforms and applications that depend on these tools.
Mitigation strategies for CVE-2019-5087 should focus on immediate patching of the xcftools 1.0.7 software to address the integer overflow condition in the flattenIncrementally function. Organizations should implement strict file validation procedures for XCF files, particularly when they are processed automatically or received from external sources. The use of sandboxing techniques for image processing operations can provide additional protection layers, while input sanitization measures should be implemented to prevent malicious data from reaching the vulnerable functions. Security monitoring should be enhanced to detect unusual file processing patterns that might indicate exploitation attempts, and regular security audits of image processing pipelines should be conducted to identify similar vulnerabilities in other software components. System administrators should also consider implementing least privilege principles for applications that process image files, limiting the potential impact should exploitation occur. The vulnerability serves as a reminder of the importance of robust integer overflow protection mechanisms in security-critical applications, particularly those handling user-supplied data, and aligns with ATT&CK technique T1059.007 for execution through malicious file processing.