CVE-2021-37569 – CVE-2021-37569 is an out-of-bounds write vulner... (How to Fix)

Q: What is the severity of CVE-2021-37569?

CVE-2021-37569 has a CVSS score of 8.2 (HIGH). CVE-2021-37569 is an out-of-bounds write vulnerability in MediaTek wireless chipsets that mishandle IEEE 1905 protocols. This allows attackers to potentially execute arbitrary code or cause denial of service on affected devices. The vulnerability affects NETGEAR and other devices using specific MediaTek chipsets with firmware version 2.0.2.

📋 TL;DR

CVE-2021-37569 is an out-of-bounds write vulnerability in MediaTek wireless chipsets that mishandle IEEE 1905 protocols. This allows attackers to potentially execute arbitrary code or cause denial of service on affected devices. The vulnerability affects NETGEAR and other devices using specific MediaTek chipsets with firmware version 2.0.2.

💻 Affected Systems

Products:

NETGEAR routers and access points with MediaTek chipsets
Other devices using affected MediaTek chipsets

Versions: Firmware version 2.0.2

Operating Systems: Embedded Linux on affected devices

Default Config Vulnerable: ⚠️ Yes

Notes: Devices must have IEEE 1905 protocol enabled, which is common in mesh networking configurations

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete device compromise, persistent backdoor installation, and lateral movement within the network

🟠

Likely Case

Denial of service causing device crashes and network disruption, with potential for limited code execution

🟢

If Mitigated

Network segmentation and proper firewall rules limit impact to isolated network segments only

🌐 Internet-Facing: HIGH - Affected devices are often internet-facing routers and access points

🏢 Internal Only: MEDIUM - Internal devices could be exploited through network traversal or compromised internal hosts

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires sending specially crafted IEEE 1905 protocol packets to vulnerable devices

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Firmware versions after 2.0.2

Vendor Advisory: https://kb.netgear.com/000064368/Security-Advisory-for-WiFi-WPS-and-IEEE-1905-Vulnerabilities-on-Multiple-Products-PSV-2021-0298-PSV-2021-0300

Restart Required: Yes

Instructions:

1. Check NETGEAR support site for your device model. 2. Download latest firmware. 3. Upload via web interface. 4. Apply update. 5. Reboot device.

🔧 Temporary Workarounds

Disable IEEE 1905 protocol

all

Turn off IEEE 1905 (EasyMesh) functionality if not required

Network segmentation

all

Isolate affected devices in separate VLANs with strict firewall rules

🧯 If You Can't Patch

Segment affected devices behind firewalls with strict ingress/egress rules
Disable WAN management and restrict administrative access to trusted internal networks only

🔍 How to Verify

Check if Vulnerable:

Check device firmware version in web interface or via SSH: cat /proc/version | grep '2.0.2'

Check Version:

cat /proc/version or check web interface under Administration > Firmware

Verify Fix Applied:

Verify firmware version is greater than 2.0.2 in device administration interface

📡 Detection & Monitoring

Log Indicators:

Unexpected device reboots
Kernel panic logs
Memory corruption errors in system logs

Network Indicators:

Unusual IEEE 1905 protocol traffic
Malformed packets to port 1905/UDP
Traffic spikes to affected devices

SIEM Query:

source="router_logs" AND ("panic" OR "segfault" OR "1905")

📊 Metadata

CVE ID: CVE-2021-37569

CVSS v3 Score: 8.2 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L

CWE: CWE-787

Published: December 26, 2021

Last Updated: November 21, 2024

🔗 References

https://corp.mediatek.com/product-security-bulletin/January-2022 Vendor Advisory
https://kb.netgear.com/000064368/Security-Advisory-for-WiFi-WPS-and-IEEE-1905-Vulnerabilities-on-Multiple-Products-PSV-2021-0298-PSV-2021-0300 Third Party Advisory
https://corp.mediatek.com/product-security-bulletin/January-2022 Vendor Advisory
https://kb.netgear.com/000064368/Security-Advisory-for-WiFi-WPS-and-IEEE-1905-Vulnerabilities-on-Multiple-Products-PSV-2021-0298-PSV-2021-0300 Third Party Advisory

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