CVE-2021-28213
📋 TL;DR
CVE-2021-28213 involves a security risk in EDK2's IpSecDxe.efi where an example encrypted private key is present, potentially allowing attackers to decrypt network traffic or impersonate systems. This affects systems using EDK2 firmware with IpSecDxe enabled, primarily enterprise servers and embedded devices implementing IPsec.
💻 Affected Systems
- EDK2 (UEFI Development Kit)
📦 What is this software?
Edk2 by Tianocore
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of IPsec-protected network communications, allowing decryption of sensitive data, man-in-the-middle attacks, and unauthorized network access.
Likely Case
Network traffic interception and decryption in environments where attackers have access to the firmware image or can extract the key from memory.
If Mitigated
Limited impact if IPsec is not used or if proper key management practices are followed with unique keys deployed.
🎯 Exploit Status
Exploitation requires access to firmware or ability to extract the example key from system memory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: EDK2 with commit addressing the issue
Vendor Advisory: https://bugzilla.tianocore.org/show_bug.cgi?id=1866
Restart Required: Yes
Instructions:
1. Update EDK2 firmware to version containing the fix. 2. Rebuild firmware images if using custom builds. 3. Deploy updated firmware to affected systems. 4. Reboot systems to apply firmware update.
🔧 Temporary Workarounds
Disable IpSecDxe
allRemove or disable the IpSecDxe driver if IPsec functionality is not required.
Requires firmware configuration changes - consult system/firmware documentation
Replace Example Key
allReplace the example encrypted private key with a unique, securely generated key.
Requires firmware reconfiguration and key management procedures
🧯 If You Can't Patch
- Ensure IPsec is configured with unique, properly managed keys instead of example keys
- Implement network segmentation to limit exposure of IPsec-protected traffic
🔍 How to Verify
Check if Vulnerable:
Check firmware version and verify if IpSecDxe driver contains the example encrypted private key. Examine firmware images or consult vendor documentation.Check Version:
System-specific firmware version check commands vary by vendor (e.g., dmidecode on Linux, systeminfo on Windows for firmware info)Verify Fix Applied:
Verify firmware has been updated to version containing the fix and that example keys are no longer present in IpSecDxe.📡 Detection & Monitoring
Log Indicators:
- Unusual network decryption attempts
- IPsec connection failures or anomalies
Network Indicators:
- Suspicious IPsec handshake patterns
- Traffic interception matching example key characteristics
SIEM Query:
Search for IPsec-related errors or anomalies in system/firmware logs