CVE-2021-33629
📋 TL;DR
CVE-2021-33629 is a vulnerability in isula-build container image builder where improper whitespace handling in external data processing functions can cause program crashes during image builds. This affects users of isula-build versions before 0.9.5-6 who build container images. The vulnerability can lead to denial of service during container image creation processes.
💻 Affected Systems
- isula-build
📦 What is this software?
Isula Build by Openeuler
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service for container image building operations, potentially disrupting CI/CD pipelines and container deployment workflows.
Likely Case
Intermittent crashes during image builds causing failed builds and requiring manual intervention to restart build processes.
If Mitigated
Minimal impact with proper monitoring and automated restart mechanisms for failed builds.
🎯 Exploit Status
Exploitation requires ability to trigger image builds with malformed input data containing problematic whitespace.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.9.5-6 and later
Vendor Advisory: https://openeuler.org/zh/security/safety-bulletin/detail.html?id=openEuler-SA-2021-1265
Restart Required: Yes
Instructions:
1. Stop all isula-build processes. 2. Update isula-build to version 0.9.5-6 or later using your package manager. 3. Restart isula-build services.
🔧 Temporary Workarounds
Input validation wrapper
linuxAdd pre-processing to strip whitespace from external data before passing to isula-build
# Add whitespace stripping in your build scripts before calling isula-build
sed -i 's/[[:space:]]*$//' input_files
🧯 If You Can't Patch
- Implement monitoring and automated restart for failed isula-build processes
- Use alternative container build tools temporarily
🔍 How to Verify
Check if Vulnerable:
Check isula-build version with: isula-build version | grep VersionCheck Version:
isula-build versionVerify Fix Applied:
Confirm version is 0.9.5-6 or higher: isula-build version | grep -E 'Version.*0\.9\.5-[6-9]|Version.*0\.9\.6|Version.*[1-9]\.[0-9]'📡 Detection & Monitoring
Log Indicators:
- Unexpected isula-build process termination
- Segmentation fault errors in isula-build logs
- Failed container builds with crash reports
Network Indicators:
- Unusual patterns of build failures in CI/CD systems
SIEM Query:
process_name="isula-build" AND (event_type="crash" OR exit_code=139)