CVE-2020-14510

Executive Summary

CVE-2020-14510 is a critical vulnerability in Secomea GateManager versions prior to 9.2c, characterized by an off-by-one error (CWE-193) that coexists with a hard-coded telnet credential allowing unprivileged attackers to execute commands as root. With a CVSS score of 9.8 and an EPSS percentile of 83.1%, this vulnerability presents a significant risk to organizations relying on GateManager for remote access management of industrial and OT environments. Currently classified as UNPATCHED with 0/4 patch confidence, successful exploitation leads to complete compromise of the affected device.

Technical Analysis

The NVD description indicates two co-located weaknesses in GateManager versions prior to 9.2c. The first is an off-by-one error classified under CWE-193, which denotes a buffer boundary miscalculation where the written data exceeds the allocated buffer by exactly one element. In the context of network-facing services, this class of flaw typically manifests in parsing routines that mishandle length-prefixed data or boundary conditions, potentially enabling memory corruption.

The second and more direct weakness is the presence of a hard-coded credential for the telnet service. This credential is embedded within the product's codebase or configuration, making it discoverable through reverse engineering or static analysis of the firmware/binaries. An unprivileged attacker—one who has not authenticated to the system—can use this credential to access the telnet interface. Critically, the telnet service appears to grant root-level privileges upon authentication, meaning the hard-coded credential effectively provides full administrative control over the device.

The combination of these flaws is significant: the telnet service is typically bound to network interfaces, making it remotely accessible. The off-by-one error may further contribute to exploitation by allowing memory corruption that could bypass additional protections, though the hard-coded credential alone represents a direct and trivial path to root access. The attack surface is the telnet service exposed on the network, which in many industrial deployments is reachable from internal networks or even the internet if improperly segmented.

Insufficient technical detail is available in the NVD description regarding the exact location of the hard-coded credential, the specific function containing the off-by-one error, or the precise telnet authentication flow. The attack mechanism, however, is clear: network reachability to the telnet service plus knowledge of the embedded credential equals immediate root access.

Exploitation Scenarios

The attack chain for CVE-2020-14510 is straightforward due to the nature of the hard-coded credential. It is essential to note that no public PoC is available; the chain is inferred from the vulnerability class and the description provided.

Step 1: Reconnaissance and Target Identification. An attacker scans for exposed GateManager instances. Since GateManager is a remote access management platform for industrial networks, targets may be identified via Shodan-style queries looking for the telnet port (TCP 23) on devices presenting GateManager-specific banners. Additional reconnaissance may involve port scans across an organization's internal network to locate devices listening on telnet. The attacker does not require prior authentication or any pre-existing foothold, given the unprivileged nature of the initial access.

Step 2: Triggering the Vulnerability. The attacker connects to the telnet service on the target device. Rather than relying on the off-by-one error for initial access, the attacker leverages the hard-coded credential, which is publicly known or extractable via firmware analysis. The authentication exchange involves supplying the embedded username/password pair. The off-by-one error (CWE-193) may be independently triggerable via malformed input during the pre-authentication or post-authentication phase, potentially enabling a memory-corruption primitive, but the primary access vector is the credential itself.

Step 3: Payload/Execution. Upon successful authentication with the hard-coded credential, the telnet session is established with root privileges. The attacker can immediately issue arbitrary shell commands via the interactive telnet session. This does not require any additional payload delivery—the command execution is inherent to the root-level shell obtained through the backdoor access. Examples of execution could include reading sensitive configuration files, disabling security controls, or establishing persistence mechanisms.

Step 4: Post-Exploitation Impact. With root access on the GateManager appliance, an attacker gains complete control over the remote access management platform. This position enables redirecting VPN tunnels, capturing credentials from managed devices, planting backdoors for persistence, lateral movement into connected industrial networks, and disrupting remote access services to cause operational downtime. Because GateManager serves as a gateway to critical infrastructure, the compromise extends beyond the single appliance to the entire connected OT environment.

Impact Assessment

The CVSS base score of 9.8 reflects the severity of this vulnerability across three dimensions: attack vector (network), attack complexity (low), and privileges required (none). The vector implies no user interaction is required, and the impact is complete across confidentiality, integrity, and availability. The device is fully compromised—an attacker can read all data transiting the gateway, modify configurations, and render the system unavailable.

The business impact is substantial for organizations using Secomea GateManager as their industrial remote access solution. These devices sit at the boundary between IT and OT networks, managing secure connections for remote maintenance and monitoring. Compromise of this infrastructure element undermines trust in the entire remote access framework. The EPSS score of 0.02487 (83.1st percentile of exploited CVEs) indicates that while not the most actively exploited vulnerability in the wild, it is in the higher percentile of likelihood, suggesting real-world interest.

The blast radius covers all deployed GateManager instances running versions prior to 9.2c. Given that a single hard-coded credential is shared across installations, the identical exploit works against every vulnerable deployment. The affected systems are network appliances, so the integrity of the entire managed network—potentially including sensitive industrial processes—is at risk. There are no known direct signs of in-the-wild exploitation; however, the trivial nature of the attack and the high CVSS score warrant immediate attention.

Detection Guidance

Sigma Rule

title: Secomea GateManager Telnet Login with Hard-coded Credential
id: c6d0a8f2-3b9e-4d4a-8f2c-1e9a3b7d5f01
status: experimental
description: Detects successful telnet logins to Secomea GateManager devices with root privileges, potentially exploiting hard-coded credentials (CVE-2020-14510).
author: Valtersit Threat Intelligence
date: 2024/01/15
logsource:
    category: process_creation
    product: linux
detection:
    selection_telnet:
        Image|endswith: '/telnetd'
        CommandLine|contains: '-l root'
    selection_login:
        # Telnetd forks a shell after successful authentication
        Image|endswith: '/sh'
        ParentImage|endswith: '/telnetd'
    condition: selection_telnet or selection_login
falsepositives:
    - Legitimate administrative telnet usage
level: high
tags:
    - attack.t1190
    - cve.2020-14510
    - cwe.193

YARA Rule

rule Secomea_GateManager_Hardcoded_Telnet_Credential {
    meta:
        author = "Valtersit Threat Intelligence"
        description = "Detects binary signatures of hardcoded telnet credentials in Secomea GateManager firmware"
        cve = "CVE-2020-14510"
        date = "2024-01-15"
    strings:
        $credential_a = { 74 65 6c 6e 65 74 3a 2f 2f } // "telnet://"
        $credential_b = "root:" ascii
        $gateway_marker = "GateManager" ascii
        $credential_hex = { 72 6f 6f 74 3a 73 65 63 6f 6d 65 61 } // "root:secomea" (generic variant pattern)
    condition:
        uint16(0) == 0x457f and // ELF magic
        (
            ($credential_a and $gateway_marker) or
            ($credential_hex and $gateway_marker)
        )
}

Suricata IDS Rule

alert tcp any any -> any 23 (msg:"CVE-2020-14510 - Secomea GateManager Telnet Hard-coded Credential Login Attempt"; flow:to_server,established; content:"|0a|"; depth:1; content:"root"; within:20; content:"|20|"; within:100; content:"secomea"; within:100; classtype:attempted-admin; sid:202014510; rev:1; metadata:created_at 2024_01_15, updated_at 2024_01_15, cve CVE-2020-14510;)

Elastic Detection

sequence by host.name with maxspan=10s
  [process where event.type == "start" and process.name == "telnetd" and process.args == "-l" and process.args == "root"]
  [process where event.type == "start" and process.name == "sh" and process.parent.name == "telnetd"]

Splunk SPL Query

index=linux sourcetype=process_creation
| where Image LIKE "%telnetd%" OR (Image LIKE "%/sh%" AND ParentImage LIKE "%telnetd%")
| eval cve_match = if(CommandLine LIKE "%root%" OR CommandLine LIKE "%secomea%", "suspicious", "normal")
| stats count by host, User, Image, ParentImage, cve_match
| where cve_match = "suspicious"
| table _time, host, User, Image, ParentImage, cve_match

Wazuh OSSEC Rule

<group name="cve-2020-14510,">
  <rule id="100510" level="12">
    <if_sid>510</if_sid>
    <match>telnetd</match>
    <regex>telnetd.*root</regex>
    <description>Secomea GateManager telnet root login — possible CVE-2020-14510 exploitation</description>
    <group>authentication_success,</group>
    <mitre><id>T1190</id></mitre>
  </rule>
  <rule id="100511" level="15">
    <if_sid>510</if_sid>
    <match>root:secomea</match>
    <description>Hard-coded credential string detected in telnet session — CVE-2020-14510</description>
    <group>pci_dss_6.5,</group>
    <mitre><id>T1190</id></mitre>
  </rule>
</group>

Mitigation & Patch Guidance

As of this report, patch confidence is 0/4 — no patch evidence has been identified from any tracked source, and the vulnerability remains UNPATCHED. Secomea has referenced version 9.2c as a patched release; however, no official advisory or patch confirmation has been obtained from the vendor, and no patch sources have been officially tracked.

Immediate Mitigations:

1. Disable telnet access. If telnet is not operationally required, disable the telnet service entirely on all GateManager instances, and use secure alternatives (SSH) instead.
2. Restrict network access. Isolate GateManager devices from untrusted networks. Apply strict firewall rules to block access to TCP port 23 from all but explicitly authorized administrative workstations.
3. Network segmentation. Move GateManager devices behind a bastion host or jump server, ensuring direct telnet access is never exposed to broader corporate or untrusted networks.

Patch / Upgrade Steps:

1. Upgrade GateManager to version 9.2c or later, which the vendor has indicated addresses this vulnerability. Test the upgrade in a staging environment prior to production deployment.
2. If upgrade is not immediately possible, apply vendor-issued hotfixes or interim security patches once they are released. Continue monitoring the vendor's advisory channels for official patch announcements.

Long-Term Hardening:

1. Eliminate telnet usage across the infrastructure, migrating to SSH with key-based authentication and hardened configurations.
2. Implement a credential management policy ensuring no hard-coded credentials are present in deployed appliances; perform firmware binary analysis during procurement for the presence of any embedded secrets.
3. Deploy network intrusion detection/prevention at choke points controlling access to management interfaces.
4. Enforce strong network segregation between IT and OT environments, allowing management access only through secure, monitored corridors.
5. Regularly audit the firmware and configuration of all OT appliances, tracking CVEs and applying patches promptly once vendor patches are available.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2020-14510
2. CWE-193 Off-by-one Error: https://cwe.mitre.org/data/definitions/193.html
3. MITRE ATT&CK Technique T1190 — Exploit Public-Facing Application: https://attack.mitre.org/techniques/T1190/
4. CISA KEV Catalog (No entry for CVE-2020-14510 as of this writing; monitor for updates)

No known threat actor campaigns or exploit-in-the-wild evidence tied to CVE-2020-14510 has been confirmed at the time of writing. Given the trivial exploitation path and the device's critical role in industrial remote access, organizations are strongly advised to prioritize remediation and treat observable anomalous telnet behavior on GateManager devices as potentially malicious.