CVE-2021-47744: Actively Exploited Hard-Coded Root Credential Enables Remote Device Takeover

Vulnerability Name: Hard-coded Root Credentials in Cypress Solutions CTM-200 / CTM-ONE
CVE ID: CVE-2021-47744
Vendor: Cypress Solutions
Affected Products: CTM-200, CTM-ONE
Affected Version: 1.3.6
Attack Vector: Network (Remote)
Authentication Required: No
User Interaction: None

Severity & Risk Overview

CVSS v3.1 Base Score: 9.8
Severity: Critical
Exploitability: High
Exploit Availability: Publicly Known / Trivially Exploitable
Impact: Complete system compromise (root access)

This vulnerability enables any remote attacker to gain unrestricted root access to affected devices. Because the credentials are hard-coded at the firmware level, they cannot be rotated or revoked, making the risk persistent until patched.

Vulnerability Description

Cypress Solutions CTM-200 and CTM-ONE devices running firmware version 1.3.6 ship with a Linux operating system that contains a hard-coded root password.

The static password embedded in the firmware is:

Chameleon

This credential is identical across all affected devices and cannot be changed by administrators. If network services such as SSH or Telnet are exposed—which is common in industrial environments—anyone who knows this password can authenticate remotely as the root user.

This is not a misconfiguration by the customer. It is a design flaw introduced during firmware development.

How the Vulnerability Can Be Exploited

Attack Flow

An attacker scans internal or external networks for exposed CTM devices.
The attacker identifies open SSH (TCP/22) or Telnet (TCP/23) services.
A login session is initiated using:
- Username: root
- Password: Chameleon
Authentication succeeds immediately.
The attacker gains full root access.

Once exploited, the attacker can:

Modify or destroy system files
Install persistent backdoors
Disable monitoring and safety mechanisms
Manipulate industrial data or processes
Pivot deeper into OT or IT environments

Exploitability & Proof-of-Concept Status

Exploit Type: Hard-coded credential abuse
Skill Level Required: Low
Tools Required: Standard SSH or Telnet client
Proof-of-Concept: Exists (simple login)

Conceptual Example

ssh root@<device-ip>
Password: Chameleon

telnet <device-ip>
login: root
password: Chameleon

No exploit framework or payload is required.

MITRE ATT&CK Mapping

Initial Access

Valid Accounts (T1078)

Privilege Escalation

Abuse Elevation Control Mechanism (T1548)

Persistence

Create or Modify System Process (T1543)

Defense Evasion

Modify Authentication Process (T1556)

This vulnerability grants attackers legitimate root access, making malicious activity blend in with normal administrative behavior.

Detection & Indicators of Compromise

Key Warning Signs

Root logins from unfamiliar IP addresses
SSH or Telnet sessions outside approved maintenance windows
Root access across multiple devices from the same source
Unauthorized configuration or firmware changes

Required Log Sources

To reliably detect exploitation attempts:

Linux authentication logs
(/var/log/auth.log, /var/log/secure)
SSH daemon logs
Telnet service logs
Network firewall logs (TCP/22, TCP/23)
IDS/IPS telemetry

Detection Logic – Splunk

Unauthorized Root Login via SSH or Telnet

index=linux_logs OR index=network_logs
(source="/var/log/auth.log" OR source="/var/log/secure")
("Accepted password" OR "Accepted publickey")
user=root
| stats count by src_ip, host, _time
| where NOT cidrmatch("10.0.0.0/8", src_ip)
AND NOT cidrmatch("192.168.0.0/16", src_ip)

Purpose:
Detects successful root logins originating outside approved administrative networks.

Root Credential Reuse Across Multiple Devices

index=linux_logs
user=root
(action=success OR "Accepted password")
| stats dc(host) as affected_devices count by src_ip
| where affected_devices > 1

Purpose:
Identifies attackers reusing the hard-coded password across multiple devices.

Telnet Access Detection

index=network_logs
dest_port=23
| stats count by src_ip, dest_ip

Purpose:
Flags insecure Telnet access paths commonly abused in OT environments.

Detection Logic – Microsoft Sentinel (KQL)

Root Login Detection (SSH)

Syslog
| where ProcessName == "sshd"
| where SyslogMessage contains "Accepted"
| where SyslogMessage contains "root"
| where not(ipv4_is_in_range(SourceIP, "10.0.0.0/8"))
| where not(ipv4_is_in_range(SourceIP, "192.168.0.0/16"))

Multiple Root Logins from Single Source

Syslog
| where SyslogMessage contains "Accepted"
| where SyslogMessage contains "root"
| summarize DeviceCount=dcount(Computer) by SourceIP
| where DeviceCount > 1

Telnet Activity Detection

CommonSecurityLog
| where DestinationPort == 23
| summarize count() by SourceIP, DestinationIP

Payloads & Post-Exploitation Activity

No exploit payload is required. After access is gained, attackers commonly:

Deploy backdoors
Modify startup scripts
Add hidden privileged users
Establish outbound command-and-control connections

Monitoring file integrity and process creation is strongly recommended.

Business & Operational Impact

Total loss of device trust
Safety risks in industrial operations
Potential physical damage
Compliance violations
Lateral movement into enterprise networks

In OT environments, this vulnerability represents a direct safety and availability risk, not just an IT issue.

Remediation & Official Patch

Official Fix

Cypress Solutions has released updated firmware that removes the hard-coded root credential.

Official Patch / Firmware Download Link

https://www.cypresssolutions.com/support/software-downloads

Required Action

Upgrade devices to a firmware version newer than 1.3.6
Verify SSH/Telnet exposure after patching

This issue cannot be fully mitigated through configuration alone. Firmware update is mandatory.

Additional Hardening Recommendations

Disable Telnet entirely
Restrict SSH access by IP
Use key-based authentication
Continuously monitor root activity
Segment OT devices from IT networks

Final Risk Summary

CVE-2021-47744 is a critical embedded systems vulnerability that provides immediate root access with no exploit code, no credentials discovery, and no user interaction.

Any environment running affected firmware should treat this as urgent and high priority.