CVE-2023-4259
📋 TL;DR
Two buffer overflow vulnerabilities in the Zephyr eS-WiFi driver allow attackers to execute arbitrary code or cause denial of service by sending specially crafted network packets. This affects systems running Zephyr RTOS with the vulnerable WiFi driver enabled. Embedded IoT devices using Zephyr are primarily at risk.
💻 Affected Systems
- Zephyr RTOS
📦 What is this software?
Zephyr by Zephyrproject
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, data exfiltration, or device bricking.
Likely Case
Denial of service causing device crashes or instability in WiFi connectivity.
If Mitigated
Limited impact with proper network segmentation and input validation controls.
🎯 Exploit Status
Exploit details and PoC code are publicly available in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Zephyr RTOS versions after the security advisory date
Vendor Advisory: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-gghm-c696-f4j4
Restart Required: Yes
Instructions:
1. Update Zephyr RTOS to the latest patched version. 2. Rebuild and redeploy firmware. 3. Restart affected devices.
🔧 Temporary Workarounds
Disable eS-WiFi driver
allTemporarily disable the vulnerable WiFi driver if not required.
Modify device configuration to disable CONFIG_WIFI_ESWIFI=y
Network segmentation
allIsolate affected devices from untrusted networks.
🧯 If You Can't Patch
- Implement strict network access controls to limit WiFi traffic to trusted sources only.
- Monitor devices for abnormal behavior or crashes indicating potential exploitation attempts.
🔍 How to Verify
Check if Vulnerable:
Check Zephyr version and configuration for eS-WiFi driver enabled in version 3.x.0.Check Version:
Check Zephyr build configuration and version identifiers in firmware.Verify Fix Applied:
Verify Zephyr version is updated beyond vulnerable versions and eS-WiFi driver functions normally.📡 Detection & Monitoring
Log Indicators:
- Device crashes, WiFi driver errors, or abnormal network packet patterns in system logs.
Network Indicators:
- Unusual WiFi traffic patterns or malformed packets targeting port 80/443 on devices.
SIEM Query:
Search for logs containing 'Zephyr', 'eS-WiFi', or device crash events from embedded systems.🔗 References
- http://packetstormsecurity.com/files/175657/Zephyr-RTOS-3.x.0-Buffer-Overflows.html
- http://seclists.org/fulldisclosure/2023/Nov/1
- http://www.openwall.com/lists/oss-security/2023/11/07/1
- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-gghm-c696-f4j4
- http://packetstormsecurity.com/files/175657/Zephyr-RTOS-3.x.0-Buffer-Overflows.html
- http://seclists.org/fulldisclosure/2023/Nov/1
- http://www.openwall.com/lists/oss-security/2023/11/07/1
- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-gghm-c696-f4j4
