CVE-2020-13600
📋 TL;DR
A heap-based buffer overflow vulnerability in Zephyr RTOS's eswifi SPI driver allows attackers to corrupt kernel memory by sending malformed SPI responses. This affects Zephyr versions 1.14.2+ and 2.3.0+, potentially leading to system crashes or remote code execution in embedded IoT devices using this real-time operating system.
💻 Affected Systems
- Zephyr RTOS
📦 What is this software?
Zephyr by Zephyrproject
Zephyr by Zephyrproject
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with kernel privileges leading to complete system compromise, data exfiltration, or device takeover in IoT deployments.
Likely Case
System crashes, denial of service, or memory corruption leading to unstable device operation in affected embedded systems.
If Mitigated
Limited impact with proper network segmentation and SPI bus isolation, potentially only causing local denial of service.
🎯 Exploit Status
Exploitation requires SPI bus access to send malformed responses. No public exploit code has been disclosed as of the advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in Zephyr v2.3.1 and later versions
Vendor Advisory: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-hx4p-j86p-2mhr
Restart Required: Yes
Instructions:
1. Update Zephyr RTOS to version 2.3.1 or later. 2. Rebuild and redeploy firmware for affected devices. 3. Verify the eswifi driver version includes the SPI response validation fix.
🔧 Temporary Workarounds
Disable eswifi SPI interface
allTemporarily disable the vulnerable eswifi driver SPI interface if not required for operation
Modify device tree configuration to disable eswifi SPI node
Set CONFIG_WIFI_ESWIFI=n in Kconfig
SPI bus isolation
allImplement hardware or software isolation for SPI bus to prevent unauthorized access
Configure SPI bus access controls
Implement SPI bus monitoring
🧯 If You Can't Patch
- Implement strict SPI bus access controls and monitoring
- Network segmentation to isolate affected devices from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check Zephyr version and eswifi driver configuration: 'west config' and examine Kconfig for CONFIG_WIFI_ESWIFICheck Version:
west version or examine Zephyr version in build configurationVerify Fix Applied:
Verify Zephyr version >=2.3.1 and check eswifi driver source for SPI response validation improvements📡 Detection & Monitoring
Log Indicators:
- SPI bus errors
- eswifi driver crashes
- Kernel panic messages related to memory corruption
Network Indicators:
- Unusual SPI traffic patterns
- Malformed SPI responses on bus
SIEM Query:
Search for: 'eswifi driver error' OR 'SPI corruption' OR 'heap overflow' in device logs