CVE-2020-29511
📋 TL;DR
This vulnerability in Go's encoding/xml package allows attackers to craft XML inputs that behave inconsistently during different processing stages. This can lead to security bypasses, data corruption, or injection attacks in applications that parse XML. All Go applications using the standard library's XML parser are potentially affected.
💻 Affected Systems
- Go programming language
- Applications using Go's encoding/xml package
📦 What is this software?
Go by Golang
Trident by Netapp
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through XML parsing leading to remote code execution or data exfiltration in vulnerable applications.
Likely Case
XML parsing inconsistencies causing application crashes, data corruption, or security control bypasses in affected systems.
If Mitigated
Limited impact with proper input validation and XML sanitization, potentially causing only parsing errors.
🎯 Exploit Status
Exploitation requires crafting malicious XML payloads that trigger the namespace prefix inconsistency.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Go 1.15.6 and 1.14.13
Vendor Advisory: https://golang.org/doc/devel/release#go1.15.minor
Restart Required: Yes
Instructions:
1. Update Go to version 1.15.6 or 1.14.13
2. Recompile all affected applications
3. Restart services using the updated binaries
🔧 Temporary Workarounds
XML Input Validation
allImplement strict XML schema validation and sanitization before parsing
Use Alternative XML Parser
allReplace encoding/xml with a third-party XML library that isn't affected
🧯 If You Can't Patch
- Implement WAF rules to block suspicious XML payloads
- Isolate vulnerable applications behind strict network segmentation
🔍 How to Verify
Check if Vulnerable:
Check Go version with 'go version' command and verify if below 1.15.6 or 1.14.13Check Version:
go versionVerify Fix Applied:
Verify Go version is 1.15.6+ or 1.14.13+ and test XML parsing functionality📡 Detection & Monitoring
Log Indicators:
- XML parsing errors
- Unexpected application crashes
- Unusual XML payload sizes or structures
Network Indicators:
- Large or malformed XML requests
- Repeated XML parsing attempts
SIEM Query:
source="application.log" AND ("xml parse error" OR "namespace" OR "encoding/xml")🔗 References
- https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-elements.md
- https://security.netapp.com/advisory/ntap-20210129-0006/
- https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-elements.md
- https://security.netapp.com/advisory/ntap-20210129-0006/
