CVE-2023-26588
📋 TL;DR
This CVE describes a hard-coded credentials vulnerability in multiple Buffalo network switch models that allows attackers to access debug functions. Attackers can exploit these static credentials to gain unauthorized access to sensitive device functions. All users of the listed Buffalo switch models with affected firmware versions are vulnerable.
💻 Affected Systems
- BS-GSL2024
- BS-GSL2016P
- BS-GSL2016
- BS-GS2008
- BS-GS2016
- BS-GS2024
- BS-GS2048
- BS-GS2008P
- BS-GS2016P
- BS-GS2024P
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing configuration changes, network traffic interception, and potential lateral movement to other network segments.
Likely Case
Unauthorized access to debug functions leading to information disclosure, configuration viewing, and potential service disruption.
If Mitigated
Limited impact with proper network segmentation and access controls preventing external access to management interfaces.
🎯 Exploit Status
Exploitation requires knowledge of the hard-coded credentials but no authentication. Attack complexity is low once credentials are known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: BS-GSL models: later than Ver. 1.10-0.03; BS-GS models: later than Ver. 1.0.10.01
Vendor Advisory: https://www.buffalo.jp/news/detail/20230310-01.html
Restart Required: Yes
Instructions:
1. Download latest firmware from Buffalo support site. 2. Backup current configuration. 3. Upload and apply firmware update via web interface or CLI. 4. Reboot device. 5. Verify firmware version is updated.
🔧 Temporary Workarounds
Network Segmentation
allIsolate management interfaces from untrusted networks
Access Control Lists
allRestrict access to management interfaces to trusted IP addresses only
🧯 If You Can't Patch
- Isolate affected devices in separate VLAN with strict access controls
- Monitor network traffic to/from management interfaces for unauthorized access attempts
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface (System Information) or CLI (show version). Compare against affected versions list.Check Version:
show version (CLI) or check System Information page (web interface)Verify Fix Applied:
Verify firmware version is updated beyond affected versions. Test debug function access with known hard-coded credentials should fail.📡 Detection & Monitoring
Log Indicators:
- Failed authentication attempts with hard-coded usernames
- Successful access to debug functions from unauthorized sources
- Configuration changes from unexpected sources
Network Indicators:
- Unusual traffic to management interfaces from external sources
- Multiple authentication attempts to switch management ports
SIEM Query:
source_ip IN (external_ips) AND dest_port IN (80,443,22,23) AND dest_ip IN (switch_management_ips) AND (event_type='authentication' OR event_type='configuration_change')