CVE-2021-42324
📋 TL;DR
This vulnerability allows authenticated low-privileged attackers with physical access to DCN S4600-10P-SI switches to escape the sandbox environment and execute arbitrary system commands as root via shell metacharacter injection in the capture command parameters. Attackers can view command output through the serial interface. Only organizations using these specific DCN switches are affected.
💻 Affected Systems
- DCN S4600-10P-SI switches
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise allowing root-level command execution, enabling network disruption, data exfiltration, or persistent backdoor installation.
Likely Case
Unauthorized configuration changes, network monitoring, or credential harvesting by malicious insiders or attackers with physical access.
If Mitigated
Limited impact due to physical access requirements and authentication controls preventing remote exploitation.
🎯 Exploit Status
Exploitation requires authenticated access to console interface and physical serial connection. Metacharacter injection technique is well-documented.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: R0241.0470 or later
Vendor Advisory: https://www.dcneurope.eu/products/switches/s4600-10p-si
Restart Required: Yes
Instructions:
1. Download firmware version R0241.0470 or later from DCN support portal. 2. Backup current configuration. 3. Upload new firmware via management interface. 4. Reboot switch to apply update. 5. Verify version with 'show version' command.
🔧 Temporary Workarounds
Restrict physical access to console ports
allPhysically secure switches in locked cabinets and disable unused console ports.
Implement least privilege access
allRemove or restrict low-privileged console accounts and implement strong authentication.
configure terminal
no username [low-privileged-user]
end
write memory
🧯 If You Can't Patch
- Implement strict physical security controls around network equipment
- Monitor console access logs and implement alerting for unauthorized serial connections
🔍 How to Verify
Check if Vulnerable:
Check firmware version with 'show version' command. If version is earlier than R0241.0470, device is vulnerable.Check Version:
show versionVerify Fix Applied:
After patching, verify version is R0241.0470 or later using 'show version' command.📡 Detection & Monitoring
Log Indicators:
- Unusual console login attempts
- Capture command executions with special characters
- Root privilege escalation attempts
Network Indicators:
- Unexpected serial console connections
- Unusual configuration changes
SIEM Query:
source="switch_logs" AND (command="capture" AND (char="|" OR char=";" OR char="&")) OR event="privilege_escalation"