CVE-2021-3624 in dcraw
Summary
by MITRE • 04/18/2022
There is an integer overflow vulnerability in dcraw. When the victim runs dcraw with a maliciously crafted X3F input image, arbitrary code may be executed in the victim's system.
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Analysis
by VulDB Data Team • 09/30/2025
The integer overflow vulnerability identified in CVE-2021-3624 affects the dcraw application, a widely used command-line tool for decoding raw image files from digital cameras. This vulnerability resides within the processing logic of X3F files, which are raw image formats specifically designed for Fujifilm's X-series cameras. The flaw represents a critical security weakness that can be exploited through maliciously crafted input files, potentially allowing remote code execution on systems where dcraw is executed. The vulnerability demonstrates the classic characteristics of an integer overflow condition where arithmetic operations exceed the maximum value that can be represented by the data type, leading to unpredictable behavior and potential exploitation.
The technical implementation of this vulnerability occurs during the parsing and processing of X3F image headers where dcraw performs calculations to determine buffer sizes or loop iterations based on values extracted from the input file. When an attacker crafts an X3F file containing manipulated header values that cause integer overflow during these calculations, the application may allocate insufficient memory buffers or execute loops with incorrect iteration counts. This misbehavior creates opportunities for memory corruption that can be leveraged to execute arbitrary code. The vulnerability is particularly dangerous because it operates at the parsing layer, meaning that simply opening or processing a malicious image file can trigger the exploit without requiring user interaction beyond the initial file execution.
From an operational perspective, this vulnerability poses significant risks to systems where dcraw is commonly deployed, including photography workflow environments, digital asset management systems, and automated image processing pipelines. The attack vector is particularly concerning because it can be delivered through seemingly legitimate image files, making it difficult to detect through traditional security measures. The integer overflow condition can lead to memory corruption that may be exploited using techniques such as return-oriented programming or stack smashing to gain control over the application's execution flow. Security researchers have noted that this vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions, and could potentially map to ATT&CK techniques involving execution through compromised applications or command injection scenarios.
Mitigation strategies for this vulnerability require immediate patching of affected dcraw versions, as the primary solution involves updating to versions that properly validate input parameters and implement overflow checks during X3F file processing. Organizations should implement strict input validation policies for all image processing workflows, particularly in environments where user-uploaded content is processed automatically. Network-based defenses can include content filtering systems that scan image files for suspicious header structures, though this approach may not be foolproof given the complexity of X3F format parsing. Additionally, system administrators should consider implementing sandboxing techniques or restricted execution environments for image processing applications to limit potential damage from successful exploitation attempts. The vulnerability also underscores the importance of regular security assessments of third-party libraries and tools used in digital media processing workflows, as integer overflows often indicate broader issues in input validation and memory management practices.