CVE-2018-3848 in CFITSIO
Summary
by MITRE
In the ffghbn function 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-2018-3848 resides within the NASA CFITSIO library version 3.42, specifically within the ffghbn function that handles FITS (Flexible Image Transport System) image parsing operations. This function processes FITS file headers and image data structures, making it a critical component for astronomical data processing applications that rely on the library for handling scientific imaging formats. The flaw manifests as a stack-based buffer overflow when the function processes malformed or specially crafted FITS images that contain malformed header values or image dimensions that exceed expected bounds.
The technical implementation of this vulnerability stems from insufficient bounds checking within the ffghbn function, which fails to validate the size parameters of image dimensions and header fields before attempting to copy data onto the stack. When an attacker constructs a FITS image with oversized dimension values or malformed header entries, the function performs a stack allocation based on these unvalidated inputs without proper size verification. This allows malicious data to overflow the allocated stack buffer and overwrite adjacent memory locations including return addresses, function parameters, and local variables, potentially enabling arbitrary code execution through stack-based memory corruption techniques.
The operational impact of this vulnerability extends beyond simple denial of service scenarios as it represents a critical remote code execution vulnerability that can be exploited through simple file delivery mechanisms. Attackers need only provide a specially crafted FITS image file to trigger the overflow condition, making this vulnerability particularly dangerous for applications that automatically process user-uploaded FITS files or fetch images from untrusted sources. The vulnerability affects any system running applications that utilize CFITSIO version 3.42 or earlier, including scientific computing environments, astronomical data processing systems, and research platforms that handle FITS formatted data. This presents significant risk in environments where automated image processing occurs, as the vulnerability can be exploited without user interaction.
Mitigation strategies for CVE-2018-3848 primarily focus on immediate software updates to CFITSIO version 3.43 or later, which includes proper bounds checking and input validation for the affected ffghbn function. Organizations should also implement defensive programming practices such as stack canaries, address space layout randomization, and heap-based memory protection mechanisms to reduce exploitability. Additionally, input sanitization should be implemented at application layers that process FITS files, including validating image dimensions and header fields before passing data to CFITSIO functions. Network-based defenses can include content filtering and sandboxing of FITS file processing to prevent automatic execution of potentially malicious files. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow and can be categorized under ATT&CK technique T1203 Exploitation for Client Execution, emphasizing the need for both patch management and runtime protection measures to address this critical security weakness in scientific imaging software libraries.