CVE-2021-46242
📋 TL;DR
CVE-2021-46242 is a heap-use-after-free vulnerability in HDF5 library's H5AC_unpin_entry component that could allow attackers to execute arbitrary code or cause denial of service. This affects applications using HDF5 v1.13.1-1 for scientific data storage and analysis. Organizations using HDF5-based software for data processing are at risk.
💻 Affected Systems
- HDF5 library
- Applications using HDF5 (MATLAB, Python h5py, scientific software)
📦 What is this software?
Hdf5 by Hdfgroup
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application crash causing denial of service and potential data corruption in HDF5 files.
If Mitigated
Limited impact with proper memory protection mechanisms and exploit mitigations in place.
🎯 Exploit Status
Exploitation requires crafting malicious HDF5 files and triggering the vulnerable code path through file processing.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: HDF5 v1.13.1-2 and later
Vendor Advisory: https://github.com/HDFGroup/hdf5/issues/1329
Restart Required: Yes
Instructions:
1. Download patched HDF5 version from HDFGroup website. 2. Uninstall vulnerable version. 3. Install patched version. 4. Recompile/redeploy applications using HDF5. 5. Restart affected services.
🔧 Temporary Workarounds
Input Validation
allValidate HDF5 files before processing using checksums or trusted sources only.
Memory Protection
linuxEnable ASLR and other memory protection mechanisms at OS level.
sysctl -w kernel.randomize_va_space=2
🧯 If You Can't Patch
- Isolate HDF5 processing to dedicated systems with network segmentation
- Implement strict file upload controls and sandbox HDF5 file processing
🔍 How to Verify
Check if Vulnerable:
Check HDF5 library version: h5dump --version or ldd on binaries using HDF5.Check Version:
h5dump --version | grep 'HDF5'Verify Fix Applied:
Verify installed HDF5 version is v1.13.1-2 or later and test with known malicious HDF5 files.📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults
- Memory corruption errors in system logs
- Unexpected process termination of HDF5 applications
Network Indicators:
- Unusual HDF5 file uploads to web applications
- Large HDF5 file transfers to processing systems
SIEM Query:
source="application.logs" AND ("segmentation fault" OR "heap corruption") AND process="*hdf5*"