GHSA-ffj4-jq7m-9g6v
GuardDog Zip Bomb Vulnerability in safe_extract() Allows DoS
Packages
Details
As written in the advisory (Markdown source, shown as plain text).
## Summary
GuardDog's `safe_extract()` function does not validate decompressed file sizes when extracting ZIP archives (wheels, eggs), allowing attackers to cause denial of service through zip bombs. A malicious package can consume gigabytes of disk space from a few megabytes of compressed data.
## Vulnerability Details
**Affected Component:** `guarddog/utils/archives.py` - `safe_extract()` function
**Vulnerability Type:** CWE-409 - Improper Handling of Highly Compressed Data (Zip Bomb)
**Severity:** HIGH (CVSS ~8)
**Attack Vector:** Network (malicious package uploaded to PyPI/npm) or local
### Root Cause
The `safe_extract()` function handles TAR files securely using the `tarsafe` library, but ZIP file extraction has no size validation:
```python
elif zipfile.is_zipfile(source_archive):
with zipfile.ZipFile(source_archive, "r") as zip:
for file in zip.namelist():
zip.extract(file, path=os.path.join(target_directory, file))
```
**Missing protections:**
- ❌ No decompressed size limit
- ❌ No compression ratio validation
- ❌ No file count limits
- ❌ No total extracted size validation
## Impact
### Denial of Service Scenarios
**1. CI/CD Pipeline Disruption**
- Attacker publishes malicious package to PyPI
- Developer adds package to requirements.txt
- CI/CD runs GuardDog scan
- Disk fills (GitHub Actions: standard 14GB limit)
- All deployments blocked
**2. Resource Exhaustion**
- Local development environments
- Security scanning infrastructure
- Automated scanning systems
- Docker containers with limited disk
**3. Supply Chain Attack Amplification**
- Single malicious package blocks security scanning
- Prevents detection of other malicious packages
- Forces manual intervention
- Increases security team workload
## Recommended Fix
Add size validation for ZIP files similar to what `tarsafe` provides for TAR files
### Configuration Options
Make limits configurable via environment variables or config file
## Additional Improvements
1. **Add warning logs** when archives approach limits
2. **Provide clear error messages** for users
3. **Document limits** in user-facing documentation
4. **Add tests** for zip bomb detection
5. **Consider using a safe ZIP library** (similar to tarsafe)
## Credit
Reported by: Charbel (dwbruijn)
References
External links from the advisory. They lead to third-party sites.