CVE-2024-9138: Privilege Escalation in Cellular Router, Secure Router, and Network Security Appliances

• January 6, 2025
• By SECNORA

Buckle up, because we’ve got some serious cybersecurity news to discuss.

Remember Moxa, that company that makes all those cool industrial networking gadgets? Well, they’ve hit a bit of a snag. On January 3, 2025, a pretty nasty vulnerability was discovered in their cellular routers, secure routers, and network security appliances. We’re talking about CVE-2024-9138, and it’s not your run-of-the-mill security hiccup. So, what’s the deal? It turns out there are hard-coded credentials hiding in the device firmware. I know, right? It’s like leaving a spare key under the doormat, except this doormat is in front of a whole bunch of critical infrastructure. Yikes!

Here’s where it gets really dicey: if you’ve already got some level of access to these devices, this flaw could let you bump up your privileges to root level. That’s basically the keys to the kingdom in tech-speak. It’s a real headache for anyone trying to keep their network operations safe and sound. Now, don’t get me wrong. Moxa’s been doing great things for industrial networking. Their EDR and OnCell series? Pretty impressive stuff. But this vulnerability is a stark reminder that even the big players can stumble when it comes to balancing cool features with rock-solid security. It’s like trying to juggle flaming torches while riding a unicycle – exciting to watch, but one wrong move and things can go south real fast. This situation highlights the ongoing tug-of-war between pushing the boundaries of what our tech can do and making sure it’s locked down tight.

So, what’s the takeaway here? If you’re using any of Moxa’s affected devices, it might be time to give your IT team a friendly nudge. And for the rest of us? Well, it’s a good reminder that in the world of cybersecurity, you can never let your guard down. Stay safe out there, folks!

Root Cause of CVE-2024-9138: Hard-Coded Credentials

The root cause of CVE-2024-9138 lies in the presence of hard-coded credentials within the firmware of certain Moxa devices, including cellular routers, secure routers, and network security appliances. These credentials, embedded directly into the system’s software, can be exploited by an attacker who already has authenticated access. Leveraging these credentials, the attacker can bypass standard privilege restrictions, gaining administrative (root) control over the device. This type of flaw is categorized under CWE-656: Reliance on Security Through Obscurity, emphasizing that security measures relying on secrecy of implementation details such as hard-coded credentials are inherently weak and prone to compromise. Specifically, the affected devices rely on hard-coded credentials embedded within the firmware. While this may simplify certain operational functionalities, it creates a critical security weakness:

1. Authentication Bypass: Authenticated users can leverage these credentials to gain unauthorized system access.
2. Privilege Escalation: Once access is obtained, attackers can elevate their privileges to root, granting unrestricted control over the system.
3. System Exploitation: The root-level access permits attackers to execute arbitrary commands, modify configurations, or even disrupt network operations, posing severe risks to organizations relying on these devices.

CVE-2024-9138’s severity is highlighted by its high CVSS scores:

• CVSS v4.0: 6 (HIGH)
• CVSS v3.1: 2 (HIGH)

Affected Products and Versions

CVE-2024-9138 is a critical vulnerability affecting several Moxa products, specifically within the EDR, EDF, NAT, OnCell, and TN series. Below is a detailed overview of each affected product and its respective versions:

1. EDR-810 Series
   Versions Affected: 1.0 through 5.12.37. The EDR-810 Series is an industrial multiport secure router that integrates firewall, NAT, VPN, and managed Layer 2 switch functions. It is designed for Ethernet-based security applications in critical remote control or monitoring networks.

2. EDR-8010 Series
   Versions Affected: 1.0 through 3.13.1. The EDR-8010 Series comprises industrial multiport secure routers with firewall, NAT, VPN, and managed Layer 2 switch capabilities. These devices are tailored for Ethernet-based security applications in critical remote control or monitoring networks.

3. EDR-G902 Series
   Versions Affected: 1.0 through 5.7.25. The EDR-G902 Series features high-performance industrial VPN servers combined with firewall and NAT functionalities. They are engineered for Ethernet-based security applications, providing an electronic security perimeter for critical cyber assets.

4. EDR-G903 Series
   Versions Affected: 1.0 through 5.7.25. Similar to the EDR-G902, the EDR-G903 Series offers high-performance industrial VPN servers with integrated firewall and NAT features, designed to secure Ethernet-based applications and protect critical cyber assets.

5. EDR-G9004 Series
   Versions Affected: 1.0 through 3.13.1. The EDR-G9004 Series consists of industrial multiport secure routers with firewall, NAT, and VPN functionalities. These devices are designed to examine industrial protocol data with Deep Packet Inspection (DPI) technology and offer easy network setup with Network Address Translation (NAT).

6. EDR-G9010 Series
   Versions Affected: 1.0 through 3.13.1.The EDR-G9010 Series includes industrial multiport secure routers that combine firewall, NAT, VPN, and managed Layer 2 switch functions, suitable for Ethernet-based security applications in critical remote control or monitoring networks.

7. EDF-G1002-BP Series
   Versions Affected: 1.0 through 3.13.1.The EDF-G1002-BP Series is an industrial-grade LAN firewall with Intrusion Prevention System (IPS) and Deep Packet Inspection (DPI) functionalities, designed to protect mission-critical assets and network zones.

8. NAT-102 Series
   Versions Affected: 1.0 through 1.0.5.The NAT-102 Series comprises ultra-compact, rugged industrial Network Address Translation (NAT) devices ideal for cabinet installation, designed to simplify IP configuration and enhance network security in industrial environments.

9. OnCell G4302-LTE4 Series
   Versions Affected: 1.0 through 3.13.The OnCell G4302-LTE4 Series includes industrial-grade cellular routers that provide reliable LTE connectivity for industrial applications, featuring dual SIM cards for redundancy and designed to operate in demanding environments.

10. TN-4900 Series
    Versions Affected: 1.0 through 3.13.The TN-4900 Series consists of EN 50155-compliant industrial secure routers with multiple Gigabit ports, designed for rolling stock railway applications, supporting features like firewall protection, dual bypass relay, and a wide operating temperature range.
    Each of these products plays a crucial role in industrial networking environments, providing essential security and connectivity features. The identified vulnerability across these versions necessitates prompt attention to ensure network integrity and security.

Core Issues of Vulnerability

CVE-2024-9138 represents a critical security vulnerability within certain Moxa network devices, characterized by the presence of hard-coded credentials in the device firmware. This flaw enables authenticated users to escalate their privileges, potentially gaining root-level access to the system. Such access allows for the execution of arbitrary commands, modification of system configurations, and the possibility of disrupting network operations.

Understanding Hard-Coded Credentials: Hard-coded credentials refer to fixed usernames and passwords embedded directly into the source code or firmware of a device. These credentials are often intended for initial setup, maintenance, or debugging purposes. However, when such credentials are not removed or adequately protected before deployment, they become a significant security risk. Attackers who discover these credentials can exploit them to gain unauthorized access to the system.

Privilege Escalation Mechanism: In the context of CVE-2024-9138, the hard-coded credentials allow an attacker with initial authenticated access—perhaps through legitimate means or by compromising a lower-level user account—to escalate their privileges. By leveraging these embedded credentials, the attacker can transition from a standard user to a superuser or root-level account. This escalation bypasses normal security controls designed to segregate user permissions and protect critical system functions.

Implications of Root-Level Access: Obtaining root-level access grants the attacker complete control over the device. The potential actions an attacker can perform include:

• Execution of Arbitrary Commands: The attacker can run any command, including those that could install malware, create backdoors, or initiate further attacks within the network.
• Modification of System Configurations: Critical settings can be altered, such as firewall rules, routing tables, or security policies, undermining the device’s intended operation and security posture.
• Disruption of Network Operations: By changing configurations or introducing malicious processes, the attacker can cause network outages, degrade performance, or redirect traffic for malicious purposes.

Security Through Obscurity and Its Pitfalls: This vulnerability is associated with CWE-656: Reliance on Security Through Obscurity. Security through obscurity involves relying on the secrecy of system design or implementation as the primary security measure. In this case, the assumption that hard-coded credentials would remain undiscovered is a flawed security practice. Once such credentials are exposed, they provide a straightforward avenue for exploitation, as seen with CVE-2024-9138.

Severity Assessment

CVE-2024-9138 is a high-severity vulnerability affecting certain Moxa network devices, characterized by the presence of hard-coded credentials that allow authenticated users to escalate privileges to root level. This vulnerability has been assessed using the Common Vulnerability Scoring System (CVSS) versions 4.0 and 3.1, receiving scores of 8.6 and 7.2 respectively, both categorized as ‘HIGH’ severity.

CVSS v4.0 Analysis

In CVSS version 4.0, the vulnerability has been assigned a base score of 8.6, indicating a high level of severity. The vector string for this score is:

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Breaking down this vector:

• Attack Vector (AV:N): Network. The vulnerability is exploitable remotely over a network connection, increasing its potential impact.
• Attack Complexity (AC:L): Low. Exploiting the vulnerability does not require specialized conditions or circumstances, making it more accessible to potential attackers.
• Attack Requirements (AT:N): None. No additional requirements are necessary beyond network access and valid credentials.
• Privileges Required (PR:H): High. The attacker needs high-level privileges to exploit this vulnerability, such as administrative access.
• User Interaction (UI:N): None. Exploitation does not require any user interaction, simplifying the attack process.
• Confidentiality Impact (VC:H): High. Successful exploitation results in a significant breach of confidentiality, potentially exposing sensitive information.
• Integrity Impact (VI:H): High. The integrity of the system can be severely compromised, allowing unauthorized modifications.
• Availability Impact (VA:H): High. The vulnerability can lead to substantial disruption of system availability, potentially causing service outages.
• Scope (SC:N): Unchanged. The exploitation of this vulnerability does not extend beyond the vulnerable component.
• Safety Impact (SI:N): None. There is no direct impact on safety.
• Environmental Impact (SA:N): None. There is no direct environmental impact.

CVSS v3.1 Analysis

In CVSS version 3.1, the vulnerability has been assigned a base score of 7.2, also indicating high severity. The vector string for this score is:

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

Breaking down this vector:

• Attack Vector (AV:N): Network. The vulnerability is exploitable remotely over a network connection.
• Attack Complexity (AC:L): Low. Exploitation does not require complex attack methods.
• Privileges Required (PR:H): High. The attacker needs high-level privileges to exploit this vulnerability.
• User Interaction (UI:N): None. No user interaction is required for exploitation.
• Scope (S:U): Unchanged. The impact is confined to the vulnerable component.
• Confidentiality Impact (C:H): High. There is a significant impact on confidentiality.
• Integrity Impact (I:H): High. There is a significant impact on integrity.
• Availability Impact (A:H): High. There is a significant impact on availability.

Interpretation of Severity Scores

Both CVSS v4.0 and v3.1 assign high severity scores to CVE-2024-9138, reflecting the substantial risk it poses. The network attack vector and low complexity indicate that the vulnerability can be exploited remotely without intricate preparations. However, the requirement for high privileges suggests that the attacker must have significant access rights to initiate the exploit. The high impacts on confidentiality, integrity, and availability underscore the potential for severe consequences, including unauthorized data access, system manipulation, and service disruption. These factors contribute to the overall high severity rating, emphasizing the need for prompt mitigation measures to protect affected systems. The CVSS assessments for CVE-2024-9138 highlight the critical nature of this vulnerability. Organizations utilizing affected Moxa devices should prioritize addressing this issue to prevent potential exploitation that could lead to significant security breaches and operational disruptions.

Mitigation Strategies for CVE-2024-9138

To protect against this vulnerability, organizations should take the following steps:

1. Update Firmware
   • Apply the newest firmware updates from Moxa Inc. for affected products right away. These updates typically fix the hard-coded credential issue.
   • Check Moxa’s website regularly or sign up for security alerts to get update notifications quickly.
2. Control Access
   • Limit admin access to network devices using secure methods.
   • Use role-based access controls to ensure only authorized staff have admin privileges.
3. Turn Off Unnecessary Services
   • Disable any services or protocols not being used on the devices.
   • Review device settings to make sure default credentials are changed or disabled.
4. Separate Networks
   • Put affected devices in isolated network segments to contain potential breaches.
   • Use firewalls and access control lists to restrict access to critical device interfaces.
5. Strengthen Passwords
   • Change all default passwords to strong, unique ones.
   • Set up multi-factor authentication for admin access where possible.
6. Check Logs Regularly
   • Review device logs often for any suspicious activity.
   • Enable logging on devices and security systems to catch potential attacks early.
7. Use Secure Communication
   • Set up devices to use encrypted protocols like SSH instead of telnet, and HTTPS instead of HTTP.
   • Verify data integrity during transmission to prevent tampering.
8. Assess Security Regularly
   • Conduct vulnerability assessments and penetration tests to find and fix weaknesses.
   • Work with cybersecurity experts to review security measures.

CVE-2024-9138 underscores the critical importance of secure device configuration and the dangers of hard-coded credentials in modern network devices. Given the high CVSS scores associated with this vulnerability, the exploitation of this flaw can lead to severe security breaches, including unauthorized access to sensitive systems and data.

Organizations that use Moxa products must be proactive in addressing this vulnerability by applying firmware updates, securing network configurations, and implementing strong authentication protocols. In addition, network segmentation, continuous monitoring, and periodic vulnerability assessments should become part of the security best practices for devices used in critical infrastructure. The conversation around CVE-2024-9138 highlights the ongoing challenges in securing networked devices, especially those deployed in industrial environments. As attackers become more sophisticated, it is crucial for organizations to adopt a holistic approach to cybersecurity that includes both preventive and detective measures. This includes adopting strong authentication measures, maintaining up-to-date security patches, and actively monitoring for signs of exploitation.

Ultimately, addressing CVE-2024-9138 is not just about fixing a single vulnerability; it is about enhancing the overall security posture of organizations and protecting the infrastructure that underpins critical networks. Through vigilance, adherence to security best practices, and close collaboration with vendors like Moxa, businesses can mitigate the risks associated with this vulnerability and safeguard their systems against future threats.

References:

https://www.cve.org/CVERecord?id=CVE-2024-9138
https://www.cve.org/CVERecord/UserGuide/#cve-cvss