CVE-2021-38111
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on DEF CON 27 badges by sending specially crafted oversized packets via the NFMI protocol. It affects all DEF CON 27 badges that have the vulnerable firmware. Attackers can potentially take full control of affected badges.
💻 Affected Systems
- DEF CON 27 Conference Badge
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of badge functionality, potential credential theft if badge stores sensitive data, and ability to use badge as pivot point for further attacks on connected systems.
Likely Case
Badge malfunction, unauthorized access to badge features, and potential data exfiltration from badge memory.
If Mitigated
Limited impact if NFMI communication is disabled or properly filtered, with only denial of service possible.
🎯 Exploit Status
Exploitation requires proximity (NFMI range ~1-2 meters) and specialized hardware like SDR (Software Defined Radio). Proof of concept code is available in GitHub repositories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: N/A
Restart Required: No
Instructions:
No official patch available. This is a hardware conference badge with limited update capability. Consider physical mitigation measures.
🔧 Temporary Workarounds
Disable NFMI Communication
allPhysically disable or shield the NFMI antenna to prevent remote exploitation
N/A - Physical modification required
Limit Physical Access
allRestrict badge proximity to untrusted devices and environments
N/A - Physical security measure
🧯 If You Can't Patch
- Retire vulnerable badges from sensitive environments
- Implement physical security zones where badge usage is restricted
🔍 How to Verify
Check if Vulnerable:
Check if you possess a DEF CON 27 conference badge. All are vulnerable.Check Version:
N/A - No version checking mechanism exists for these badgesVerify Fix Applied:
No fix available to verify. Physical modifications can be inspected visually.📡 Detection & Monitoring
Log Indicators:
- N/A - Badges do not generate traditional logs
Network Indicators:
- Unusual NFMI protocol traffic patterns
- Oversized packet transmissions in NFMI range
SIEM Query:
N/A - Not applicable for hardware badges without logging capability