CVE-2019-20004 in IWR 3000N
Summary
by MITRE
An issue was discovered on Intelbras IWR 3000N 1.8.7 devices. When the administrator password is changed from a certain client IP address, administrative authorization remains available to any client at that IP address, leading to complete control of the router.
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Analysis
by VulDB Data Team • 03/19/2024
This vulnerability exists within Intelbras IWR 3000N wireless routers running firmware version 1.8.7, representing a critical authorization flaw that undermines the device's security model. The issue stems from improper session management where the system fails to invalidate existing administrative sessions when a password change occurs. This creates a persistent security weakness that allows unauthorized users to maintain administrative access even after legitimate administrators have updated their credentials. The vulnerability specifically manifests when an administrator changes their password from a particular IP address, yet the system continues to grant administrative privileges to any client connecting from that same IP address. This behavior violates fundamental security principles and creates a persistent backdoor that can be exploited by attackers who gain access to the network segment containing the vulnerable device. The flaw essentially creates a session hijacking scenario where administrative access remains valid regardless of credential changes, effectively nullifying the purpose of password updates as a security control measure.
The technical implementation of this vulnerability demonstrates a failure in the device's authentication state management system. When an administrator modifies their password, the system should invalidate all existing sessions and require re-authentication from all clients. However, the IWR 3000N firmware fails to properly handle this session invalidation process, particularly concerning IP-based authorization mechanisms. This represents a classic case of inadequate session management as classified under CWE-613, where insufficiently protected session identifiers or improper session handling leads to persistent access rights. The vulnerability also aligns with CWE-306, which addresses missing authentication for critical functions, since the system fails to properly enforce authentication even after credential modification. The root cause appears to be a flaw in how the device's web interface handles authentication state transitions, particularly when password change operations occur. This issue can be categorized under the ATT&CK framework as a privilege escalation technique, specifically targeting the 'Exploitation for Privilege Escalation' tactic where attackers can maintain elevated access through improper session handling.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with complete administrative control over the affected routers. Once an attacker identifies a client IP address from which an administrator has accessed the device, they can maintain persistent access to the router's administrative interface without needing to know the current password. This persistent access allows for complete network compromise including configuration changes, traffic interception, DNS poisoning, and potential lateral movement within the network. The vulnerability is particularly dangerous because it can be exploited from any location within the same network segment, making it difficult to detect and isolate. Network administrators who rely on password changes as a security measure will find their efforts undermined, as the system continues to grant administrative access regardless of credential updates. The impact extends beyond simple unauthorized access to include potential data exfiltration, network disruption, and the ability to establish persistent backdoors for future exploitation. This vulnerability effectively transforms a single point of compromise into a persistent threat that can remain undetected for extended periods, making it a significant concern for enterprise network security.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The most effective immediate solution involves updating the firmware to a version that properly implements session invalidation during password changes, which would require contacting Intelbras for an official security patch. Network segmentation and access control measures should be implemented to limit the exposure of these devices to unauthorized network segments, particularly by implementing network access control lists that restrict administrative access to specific trusted IP addresses. Administrators should consider implementing additional authentication mechanisms such as two-factor authentication where supported, and regularly monitor network access logs for unusual patterns of access from the same IP addresses. The device should be configured to use strong, complex passwords and to enforce password policies that include regular changes and complexity requirements. Organizations should also implement network monitoring solutions that can detect anomalous access patterns and alert administrators to potential unauthorized access attempts. From a compliance perspective, this vulnerability would likely violate security standards such as nist 800-53 and iso 27001 requirements for proper access control and session management. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other network devices, as this type of session management flaw is not uncommon in embedded network appliances and could indicate broader security weaknesses in the network infrastructure.