CVE-2020-18494
📋 TL;DR
CVE-2020-18494 is a buffer overflow vulnerability in HDF5 library's H5S_close function that allows remote attackers to execute arbitrary code by tricking users or systems into processing a maliciously crafted HDF5 file. This affects any application or system using HDF5 1.10.4 for scientific data processing. Attackers could gain full control of affected systems through crafted file exploitation.
💻 Affected Systems
- HDF5 library
- Applications using HDF5 (Python h5py, MATLAB, 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, and lateral movement within networks.
Likely Case
Application crash leading to denial of service, with potential for RCE if exploit is weaponized.
If Mitigated
Application crash without code execution if ASLR/DEP protections are effective.
🎯 Exploit Status
Public PoC exists in GitHub repository. Exploitation requires user to open crafted file or automated processing of untrusted files.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: HDF5 1.10.5 and later
Vendor Advisory: https://portal.hdfgroup.org/display/support/security
Restart Required: Yes
Instructions:
1. Download HDF5 1.10.5+ from https://www.hdfgroup.org/downloads/hdf5/ 2. Compile and install new version 3. Recompile applications against patched library 4. Restart affected services
🔧 Temporary Workarounds
Input validation for HDF5 files
allImplement strict validation of HDF5 files before processing
Sandbox HDF5 processing
linuxRun HDF5 file processing in isolated containers or sandboxes
docker run --rm -v /path/to/files:/data your-app
🧯 If You Can't Patch
- Implement strict file upload controls and scan all incoming HDF5 files
- Isolate systems processing HDF5 files using network segmentation and minimal privileges
🔍 How to Verify
Check if Vulnerable:
Check HDF5 library version: h5dump --version or ldd /path/to/application | grep hdf5Check Version:
h5dump --version 2>/dev/null || strings /usr/lib/*hdf5* 2>/dev/null | grep 'HDF5 Version'Verify Fix Applied:
Verify version is 1.10.5 or higher: h5dump --version | grep -q '1.10.[5-9]\|1.1[1-9]'📡 Detection & Monitoring
Log Indicators:
- Application crashes with HDF5 library errors
- Segmentation faults in HDF5-related processes
Network Indicators:
- Unexpected HDF5 file transfers to sensitive systems
SIEM Query:
process_name:h5* AND (event_type:crash OR exit_code:139)