CVE-2018-20219 in ENC-400
Summary
by MITRE
An issue was discovered on Teracue ENC-400 devices with firmware 2.56 and below. After successful authentication, the device sends an authentication cookie to the end user such that they can access the devices web administration panel. This token is hard-coded to a string in the source code (/usr/share/www/check.lp file). By setting this cookie in a browser, an attacker is able to maintain access to every ENC-400 device without knowing the password, which results in authentication bypass. Even if a user changes the password on the device, this token is static and unchanged.
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Analysis
by VulDB Data Team • 09/23/2024
This vulnerability affects Teracue ENC-400 network devices running firmware versions 2.56 and earlier, representing a critical authentication flaw that undermines the device's security architecture. The issue stems from a hard-coded authentication token stored within the device's source code at the specific file path /usr/share/www/check.lp. This hardcoded credential represents a fundamental design flaw that violates security best practices and creates a persistent backdoor for unauthorized access. The vulnerability operates by leveraging the device's normal authentication flow where legitimate users receive a session cookie upon successful login, but this cookie value remains static and predictable across all device instances.
The technical implementation of this flaw demonstrates poor secure coding practices and violates multiple security principles including the principle of least privilege and secure credential management. The hardcoded token serves as a universal access key that bypasses the entire authentication mechanism, allowing attackers to gain administrative access to any ENC-400 device without knowledge of legitimate user credentials. This creates a persistent threat vector that remains active regardless of password changes or account modifications, as the token remains unchanged in the source code. The vulnerability essentially provides a permanent backdoor that can be exploited by any attacker who discovers the hardcoded string, making it particularly dangerous in environments where these devices are deployed.
From an operational impact perspective, this vulnerability enables complete administrative control over affected devices, potentially allowing attackers to modify network configurations, access sensitive data, install malicious firmware, or use the devices as entry points for broader network attacks. The persistence of the vulnerability means that even if device administrators attempt to secure their systems by changing passwords, the underlying flaw remains unaddressed, creating a false sense of security. This authentication bypass can lead to serious consequences including data breaches, network disruption, and potential use as a pivot point for lateral movement within corporate networks. The vulnerability affects all devices running the vulnerable firmware versions, making it a widespread concern for organizations that have deployed these specific network devices.
The security implications of this vulnerability align with CWE-798, which addresses the use of hard-coded credentials, and represents a classic example of insecure credential storage. From an attack perspective, this vulnerability maps directly to the ATT&CK technique T1078.004 for Valid Accounts: Default Accounts and T1566 for Phishing, as it provides attackers with a default access mechanism that bypasses normal authentication processes. Organizations should immediately implement mitigations including firmware updates to versions that address this hardcoded token issue, network segmentation to limit access to these devices, and monitoring for unauthorized access attempts. Additionally, administrators should consider implementing network access controls and regular security assessments to identify similar hardcoded credentials in other network infrastructure components. The vulnerability underscores the critical importance of avoiding hardcoded credentials in embedded systems and the necessity of implementing proper session management and authentication mechanisms in network devices.