CVE-2023-0344 in E11
Summary
by MITRE • 03/31/2023
Akuvox E11 appears to be using a custom version of dropbear SSH server. This server allows an insecure option that by default is not in the official dropbear SSH server.
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Analysis
by VulDB Data Team • 04/02/2023
The vulnerability identified as CVE-2023-0344 affects the Akuvox E11 device which implements a customized version of the dropbear SSH server. This custom implementation introduces a security risk through the inclusion of an insecure option that is not present in the official dropbear SSH server distribution. The device manufacturer has modified the standard dropbear implementation to include functionality that creates potential security weaknesses within the remote access capabilities of the system. This deviation from the standard dropbear codebase represents a significant concern as it introduces unknown security implications that may not have been properly evaluated or tested.
The technical flaw manifests in the custom dropbear implementation where specific insecure options are enabled by default or can be enabled through configuration. These options likely relate to weak cryptographic practices, insecure key exchange mechanisms, or other SSH protocol violations that would normally be disabled in the official dropbear server. The vulnerability stems from the device manufacturer's decision to extend the standard dropbear functionality with additional features that compromise security. This could include enabling weak cipher suites, allowing insecure key exchange algorithms, or implementing other configurations that weaken the overall security posture of the SSH implementation.
The operational impact of this vulnerability is substantial as it affects the remote management capabilities of Akuvox E11 devices. Attackers who can exploit this vulnerability may gain unauthorized access to the device through SSH connections, potentially leading to complete system compromise. The insecure SSH implementation creates an entry point for malicious actors to perform various attacks including privilege escalation, data exfiltration, or use the device as a pivot point for further network exploration. Given that many security-critical devices rely on SSH for remote management, this vulnerability could enable attackers to compromise entire network infrastructures if multiple Akuvox E11 devices are deployed within the same environment.
The vulnerability aligns with CWE-310 which covers cryptographic weaknesses and CWE-295 which addresses improper certificate validation. From an ATT&CK perspective, this vulnerability maps to T1021.004 for remote services and T1566 for phishing with malicious attachments, as attackers could potentially leverage this weakness to establish persistent access. Organizations should implement immediate mitigations including disabling SSH access where possible, implementing network segmentation, and monitoring for unauthorized SSH connections. The recommended approach involves upgrading to firmware versions that address this specific vulnerability or implementing compensating controls such as SSH bastion hosts and strict access controls. Security teams should also conduct comprehensive vulnerability assessments to identify other potentially affected devices within their network infrastructure that may have been similarly modified from standard dropbear implementations.
The root cause of this vulnerability lies in the manufacturer's decision to extend the standard dropbear SSH server with insecure functionality without proper security evaluation. This represents a common pattern in embedded device security where manufacturers add custom features that may introduce unknown risks. The vulnerability highlights the importance of maintaining security standards in custom implementations and the necessity of rigorous security testing for any modifications to standard security software components. Organizations should consider this as a broader indicator of potential security gaps in their embedded device deployments and implement more comprehensive security assessment procedures for all third-party firmware implementations.