CVE-2021-46244 in HDF5
Summary
by MITRE • 01/22/2022
A Divide By Zero vulnerability exists in HDF5 v1.13.1-1 vis the function H5T__complete_copy () at /hdf5/src/H5T.c. This vulnerability causes an aritmetic exception, leading to a Denial of Service (DoS).
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Analysis
by VulDB Data Team • 01/27/2022
The vulnerability identified as CVE-2021-46244 represents a critical divide by zero error within the HDF5 library version 1.13.1-1, specifically within the H5T__complete_copy function located in the /hdf5/src/H5T.c source file. This flaw constitutes a fundamental mathematical error where the software attempts to perform division operations with zero as the divisor, creating an arithmetic exception that fundamentally disrupts the normal execution flow of the application. The vulnerability exists in the type conversion and copying mechanisms of HDF5, which are essential components for handling data type descriptions and memory management within the hierarchical data format system. When an attacker provides malformed or specially crafted input data that triggers this specific code path, the arithmetic exception manifests as an immediate system crash or termination of the targeted process. The impact extends beyond simple application failure as this vulnerability can be exploited to achieve a complete denial of service condition, effectively rendering the affected system or application unusable for legitimate users. This type of vulnerability falls under CWE-369, which specifically addresses the divide by zero weakness, and aligns with ATT&CK technique T1499.004 for network denial of service attacks. The function H5T__complete_copy serves as a critical component in HDF5's type system, responsible for copying type descriptions and ensuring proper memory allocation for complex data structures. When this function encounters a scenario where division operations are performed without proper validation of denominator values, it creates an exploitable condition that can be triggered through crafted input files or data streams that are processed by the HDF5 library. The vulnerability demonstrates a lack of proper input validation and error handling within the library's internal type management subsystem, which is particularly concerning given HDF5's widespread use in scientific computing, data storage, and analysis applications where reliability and stability are paramount. This flaw can be particularly dangerous in environments where HDF5 is used for critical data processing or when the library is integrated into larger systems that cannot tolerate unexpected termination or crashes.
The operational impact of CVE-2021-46244 extends far beyond a simple application crash, as it can effectively incapacitate entire data processing workflows and systems that rely on HDF5 for data management. When this divide by zero condition occurs during the execution of H5T__complete_copy, the resulting arithmetic exception typically leads to an immediate process termination, leaving users unable to access or manipulate their data through the affected software. The vulnerability is particularly insidious because it can be triggered through legitimate data processing operations, meaning that even trusted users with valid data inputs could inadvertently cause system failures. This creates a scenario where a DoS attack can be executed without requiring specialized malicious input beyond what would normally be expected in normal usage patterns. The implications are severe for organizations relying on HDF5-based systems for scientific research, data analysis, or storage management, as the disruption can cascade through entire computational pipelines and affect multiple dependent services. The vulnerability's exploitation potential is heightened by the fact that HDF5 is commonly integrated into various scientific applications, data visualization tools, and enterprise systems where the library serves as a foundational component for data handling operations. Security researchers have noted that such arithmetic exceptions in core library functions can be particularly challenging to detect and remediate, as they often occur in complex code paths that are not immediately obvious to developers or security auditors.
Mitigation strategies for CVE-2021-46244 should focus on immediate patching of the affected HDF5 library version 1.13.1-1 to address the divide by zero condition within the H5T__complete_copy function. Organizations should prioritize updating to the latest stable release of HDF5 that includes the fix for this specific vulnerability, which typically involves implementing proper validation checks for division operations and ensuring that denominator values are explicitly tested for zero before performing arithmetic operations. System administrators should also consider implementing input validation measures at the application level to detect and reject malformed data that could potentially trigger this condition, particularly when processing untrusted data sources. The remediation process should include thorough testing of updated systems to ensure that the patch does not introduce any regressions or compatibility issues with existing applications that depend on HDF5 functionality. Additional defensive measures can include network segmentation to limit exposure, monitoring for unusual process termination patterns, and implementing intrusion detection systems that can identify potential exploitation attempts targeting this specific vulnerability. Organizations should also conduct comprehensive vulnerability assessments to identify other instances where similar arithmetic exception conditions might exist within their software ecosystems, particularly in libraries and components that perform mathematical operations without proper validation. The fix for this vulnerability typically involves adding conditional checks to ensure that division operations only proceed when the denominator is non-zero, which aligns with standard secure coding practices and defensive programming principles that are recommended by both CWE guidelines and industry security frameworks. Regular security updates and patch management processes should be reinforced to prevent similar vulnerabilities from being introduced in future versions of the library.