CVE-2018-3846 in CFITSIO
Summary
by MITRE
In the ffgphd and ffgtkn functions in NASA CFITSIO 3.42, specially crafted images parsed via the library can cause a stack-based buffer overflow overwriting arbitrary data. An attacker can deliver an FIT image to trigger this vulnerability and potentially gain code execution.
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Analysis
by VulDB Data Team • 02/28/2023
The vulnerability identified as CVE-2018-3846 resides within the NASA CFITSIO library version 3.42, specifically affecting the ffgphd and ffgtkn functions. This flaw represents a critical stack-based buffer overflow that occurs when processing specially crafted FITS (Flexible Image Transport System) image files. The CFITSIO library serves as a widely-used software package for reading and writing data files in the FITS format, which is standard in astronomy and scientific data processing. The vulnerability arises from inadequate bounds checking during the parsing of FITS image headers and data structures, creating a condition where maliciously constructed image files can overwrite adjacent memory locations on the stack.
The technical implementation of this vulnerability stems from improper input validation within the image parsing routines. When the ffgphd and ffgtkn functions process FITS files, they fail to adequately verify the size and structure of image data before copying it into fixed-size buffers allocated on the stack. This allows an attacker to craft a FITS image containing oversized or malformed header data that exceeds the allocated buffer boundaries. The overflow can overwrite not only adjacent stack variables but potentially overwrite return addresses and other critical control data, enabling arbitrary code execution. The vulnerability is particularly concerning because FITS files are commonly used in scientific research and astronomical data processing, making the attack surface broad and potentially targeting research institutions, observatories, and scientific computing environments.
The operational impact of this vulnerability extends beyond simple code execution, as it can be exploited in various attack scenarios. An attacker could deliver a malicious FITS file through email attachments, scientific data repositories, or collaborative platforms where such files are commonly shared. The vulnerability is particularly dangerous in environments where automated processing of FITS files occurs, such as in data pipelines, scientific computing clusters, or research laboratory systems. The exploitability of this vulnerability aligns with attack techniques described in the MITRE ATT&CK framework under the 'Exploitation for Code Execution' tactic, where adversaries leverage software vulnerabilities to execute malicious code. The CWE (Common Weakness Enumeration) classification for this vulnerability falls under CWE-121, Stack-based Buffer Overflow, which is a well-documented and frequently exploited weakness in software systems.
Mitigation strategies for CVE-2018-3846 should focus on immediate patching of the CFITSIO library to version 3.43 or later, which includes proper bounds checking and input validation. Organizations should implement strict file validation procedures for FITS files, particularly in automated processing environments, by verifying file integrity and structure before parsing. Network segmentation and access controls should be enforced to limit the exposure of systems that process FITS files, while also implementing monitoring for suspicious file access patterns. Security teams should also consider implementing application whitelisting policies that restrict execution of untrusted FITS files, and conduct regular vulnerability assessments of scientific computing environments that may be using affected versions of the library. The remediation approach should align with industry best practices for buffer overflow protection and secure coding standards, ensuring that all input data is properly validated and sanitized before processing.