CVE-2023-23110 – This CVE describes a firmware modification vuln... (How to Fix)

Q: What is the severity of CVE-2023-23110?

CVE-2023-23110 has a CVSS score of 7.4 (HIGH). This CVE describes a firmware modification vulnerability in multiple Netgear router models where firmware integrity checks use a fixed checksum. Attackers can perform man-in-the-middle attacks to modify firmware images during upload and bypass verification. This affects users of specific Netgear router models with vulnerable firmware versions.

📋 TL;DR

This CVE describes a firmware modification vulnerability in multiple Netgear router models where firmware integrity checks use a fixed checksum. Attackers can perform man-in-the-middle attacks to modify firmware images during upload and bypass verification. This affects users of specific Netgear router models with vulnerable firmware versions.

💻 Affected Systems

Products:

WNR612v2 Wireless Routers
DGN1000v3 Modem Router
D6100 WiFi DSL Modem Routers
WNR1000v2 Wireless Routers
XAVN2001v2 Wireless-N Extenders
WNR2200 Wireless Routers
WNR2500 Wireless Routers
R8900 Smart WiFi Routers
R9000 Smart WiFi Routers

Versions: WNR612v2: 1.0.0.3 and earlier, DGN1000v3: 1.0.0.22 and earlier, D6100: 1.0.0.63 and earlier, WNR1000v2: 1.1.2.60 and earlier, XAVN2001v2: 0.4.0.7 and earlier, WNR2200: 1.0.1.102 and earlier, WNR2500: 1.0.0.34 and earlier, R8900: 1.0.3.6 and earlier, R9000: 1.0.3.6 and earlier

Operating Systems: Embedded router firmware

Default Config Vulnerable: ⚠️ Yes

Notes: All affected devices with default configurations are vulnerable during firmware update process

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete device compromise allowing persistent backdoor installation, credential theft, network traffic interception, and use as attack platform

🟠

Likely Case

Unauthorized firmware modification leading to device instability, data interception, or credential harvesting

🟢

If Mitigated

Limited impact if firmware updates are performed over trusted networks with proper monitoring

🌐 Internet-Facing: MEDIUM - Requires user-initiated firmware update over vulnerable connection

🏢 Internal Only: LOW - Internal network attacks would require local network access

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires man-in-the-middle position during firmware update and knowledge of fixed checksum

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check Netgear support for each specific model

Vendor Advisory: https://www.netgear.com/about/security/

Restart Required: Yes

Instructions:

1. Visit Netgear support website 2. Enter your model number 3. Download latest firmware 4. Log into router admin interface 5. Navigate to firmware update section 6. Upload and install new firmware 7. Reboot device

🔧 Temporary Workarounds

Secure firmware update procedure

all

Only perform firmware updates over trusted, wired connections to prevent MITM attacks

Network segmentation

all

Isolate router management interface from untrusted networks

🧯 If You Can't Patch

Replace affected devices with supported models
Implement strict network monitoring for firmware update attempts

🔍 How to Verify

Check if Vulnerable:

Check router admin interface for firmware version and compare with affected versions list

Check Version:

Log into router web interface and check Administration or Advanced settings for firmware version

Verify Fix Applied:

Verify firmware version after update matches latest available from Netgear

📡 Detection & Monitoring

Log Indicators:

Unexpected firmware update attempts
Multiple failed firmware validations
Unusual checksum verification failures

Network Indicators:

Unusual traffic during firmware update windows
MITM attack patterns on router management ports

SIEM Query:

source="router_logs" AND (event="firmware_update" OR event="checksum_failure")

📊 Metadata

CVE ID: CVE-2023-23110

CVSS v3 Score: 7.4 (HIGH)

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

CWE: CWE-494

Published: February 2, 2023

Last Updated: March 26, 2025

🔗 References

https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/BkBPIeGco Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/H1lIcXbco Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/HyZRxmb9s Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/S1BNhbWqi Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/S1qWglM5o Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/S1t47Ebqj Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/SJCGkb-9o Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/r1Z4BX-5i Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/ryjVZz-5s Exploit,Third Party Advisory
https://www.netgear.com/about/security/ Vendor Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/BkBPIeGco Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/H1lIcXbco Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/HyZRxmb9s Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/S1BNhbWqi Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/S1qWglM5o Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/S1t47Ebqj Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/SJCGkb-9o Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/r1Z4BX-5i Exploit,Third Party Advisory
https://hackmd.io/%40slASVrz_SrW7NQCsunofeA/ryjVZz-5s Exploit,Third Party Advisory
https://www.netgear.com/about/security/ Vendor Advisory

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