Erlang SSH Flaw Threatens OT Networks

In April 2025, researchers disclosed a critical vulnerability in Erlang/OTP, a widely used programming framework embedded in telecommunications equipment, messaging systems, and industrial platforms. The flaw, tracked as CVE-2024-9451, resides in the implementation of SSH authentication and enables unauthenticated remote attackers to gain full code execution on affected systems.

Soon after disclosure, attackers began exploiting the vulnerability in the wild. By early May, multiple security vendors confirmed targeted attacks against operational technology (OT) networks, prompting urgent warnings across energy, manufacturing, and logistics sectors. This wasn’t theoretical exposure. It was active, weaponized, and aimed directly at systems responsible for real-world output.

What is the Erlang/OTP SSH Vulnerability?

At its core, the vulnerability stems from how Erlang/OTP handles user authentication via SSH, a protocol commonly used to manage remote devices securely. The flaw arises when public key authentication is enabled, and keyboard-interactive authentication is disabled.

In this configuration, the SSH implementation fails to correctly validate the authentication flow, allowing remote attackers to bypass authentication entirely. The result: remote code execution on any exposed device or service using the vulnerable Erlang runtime.

• Vulnerability ID: CVE-2024-9451

• Severity: Critical

• Vector: Network (remote)

• Affected environments: Erlang/OTP 25.3 through 26.2.2

• Attack method: Exploiting SSH logic to execute arbitrary commands without credentials

According to SecurityWeek’s analysis, public exploit code was quickly published. Within days, mass scanning began across public IP ranges and VPN-exposed OT gateways.

Widespread Exploitation in OT Environments

While Erlang/OTP isn’t often named in software bills of materials, it quietly powers numerous critical infrastructure components, especially in messaging, telemetry, and control systems.

As SecurityWeek reported, adversaries exploited this flaw to gain a foothold in multiple OT/IoT networks, including:

• Electric utilities where Erlang is used in telemetry and monitoring backends

• Smart grid systems, particularly those using Erlang-based platforms for distributed control

• Industrial automation environments where SSH is exposed for remote diagnostics or updates

• Logistics and transportation where IoT gateways rely on Erlang-based protocols

Once attackers gained access, they were observed deploying malware, altering configurations, and in some cases, disabling or disrupting remote access entirely. The common denominator: vulnerable systems were directly accessible over SSH, often through VPNs, cloud platforms, or third-party maintenance channels.

The Real-World Risk

What makes this vulnerability particularly dangerous isn’t just its exploitability; it’s where it lands. Operational systems can’t afford disruption. When attackers breach OT environments, the impact is not limited to data theft or defacement. It affects production uptime, safety systems, and revenue continuity.

A single compromised interface in a factory or substation can:

• Interrupt manufacturing lines, halting delivery schedules

• Disable critical alerts or telemetry data used for safety

• Trigger shutdowns or force manual overrides that slow operations

According to IBM’s 2025 Cost of a Data Breach Report, the average cost of an industrial sector breach reached $4.4 million, with operational outages representing the largest financial hit. In a similar research study, after surveying 3200 global plant maintenance leaders, ABB found that the cost of downtime was $125,000 per hour.

And these numbers don’t account for reputation damage, regulatory consequences, or contract penalties, all of which intensify when remote access is involved.

Securing Remote Access and OT Environments Against Exploits

At DataFlowX, we design our products to address the exact conditions that enabled CVE-2024-9451 to become an attack vector: remote entry points, unmanaged protocols, and blind spots between IT and OT.

Diode-Based Unidirectional Gateway

Vulnerabilities like CVE-2024-9451 can only be exploited if an attacker can reach the system. DataDiodeX prevents that by ensuring information flows out of the OT network but never back in.

• Hardware-enforced isolation

• Airgap-compatible, CC EAL4+ certified

• Supports OT/ICS protocols and industrial integration

• Eliminates SSH exposure and command injection risk

With DataDiodeX in place, critical nodes become unreachable from the outside regardless of software bugs or misconfigurations.

Fortified Sandbox Solution

In environments where files must still enter, DataSecureX analyzes executables, scripts, and update packages before they reach production systems.

• Multi-engine scanning and YARA analysis

• Integration with threat intelligence

• Detection of obfuscated backdoors, SSH tools, or malicious scripts

• Simulating behavior before deployment

If a threat actor tries to sneak in a secondary payload (such as an SSH tunneling tool), DataSecureX catches it before it becomes a breach.

Zero-USB Policy

In airgapped or semi-isolated networks, removable media is still being used as a bridge between systems. DataStationX ensures that the bridge is secure.

• Scans files in plugged removable media for malware and SSH-based exploits

• Blocks suspicious installers or tools based on policy

• Offers audit logging for compliance and investigation

• Designed for industrial and regulatory environments

Take Your Guard

The Erlang/OTP SSH flaw didn’t just expose a coding error; it exposed a systemic truth: remote access is only as secure as the software behind it. And in OT, that’s not good enough.

If you're relying on VPNs, exposed SSH services, or unfiltered file transfers, you're leaving your operations vulnerable to the next zero-day. The only way to stay ahead is to physically constrain what software cannot guarantee.

Contact the expert DataFlowX team today to find out how you can integrate hardened boundaries, one-way control, and proactive validation without compromising operational efficiency.