CVE-2024-3572
📋 TL;DR
This vulnerability in the Scrapy web scraping framework allows attackers to perform XML External Entity (XXE) attacks by submitting malicious XML data. It affects systems using Scrapy to parse untrusted XML input, potentially leading to denial of service, local file access, or network reconnaissance. Any application using vulnerable Scrapy versions with XML parsing functionality is at risk.
💻 Affected Systems
- Scrapy
📦 What is this software?
Scrapy by Scrapy
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through file exfiltration, denial of service, or internal network reconnaissance via XXE attacks.
Likely Case
Denial of service attacks causing application instability or limited file access from the server's filesystem.
If Mitigated
Minimal impact with proper input validation and XML parser configuration in place.
🎯 Exploit Status
XXE attacks are well-documented and easy to weaponize with available tools.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions including commit 809bfac4890f75fc73607318a04d2ccba71b3d9f
Vendor Advisory: https://github.com/scrapy/scrapy/commit/809bfac4890f75fc73607318a04d2ccba71b3d9f
Restart Required: No
Instructions:
1. Update Scrapy to latest version. 2. Verify commit 809bfac4890f75fc73607318a04d2ccba71b3d9f is included. 3. Test XML parsing functionality.
🔧 Temporary Workarounds
Disable XXE in lxml parser
allConfigure lxml parser to disable external entity resolution
parser = etree.XMLParser(resolve_entities=False, no_network=True)
Input validation
allValidate and sanitize XML input before parsing
🧯 If You Can't Patch
- Implement strict input validation for all XML data
- Use alternative XML parsers with XXE protection enabled
🔍 How to Verify
Check if Vulnerable:
Check if Scrapy version predates commit 809bfac4890f75fc73607318a04d2ccba71b3d9f and uses lxml.etree.fromstring for XML parsing.Check Version:
pip show scrapy | grep VersionVerify Fix Applied:
Verify Scrapy version includes the security commit and test with XXE payloads that should be rejected.📡 Detection & Monitoring
Log Indicators:
- Unusual XML parsing errors
- Large XML file processing
- External entity resolution attempts
Network Indicators:
- Outbound connections from XML parsing processes
- Unexpected file read operations
SIEM Query:
source="application.log" AND "XML" AND ("entity" OR "external" OR "DOCTYPE")