CVE-2015-7923 in WeOS
Summary
by MITRE
Westermo WeOS before 4.19.0 uses the same SSL private key across different customers' installations, which makes it easier for man-in-the-middle attackers to defeat cryptographic protection mechanisms by leveraging knowledge of a key.
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Analysis
by VulDB Data Team • 07/11/2018
The vulnerability identified as CVE-2015-7923 affects Westermo WeOS versions prior to 4.19.0, presenting a critical weakness in the network security infrastructure of industrial devices. This issue stems from the improper implementation of cryptographic key management practices where the same SSL private key is deployed across multiple customer installations, fundamentally undermining the security assurances that cryptographic protocols are designed to provide. The flaw represents a severe deviation from established security best practices and creates a significant attack surface that adversaries can exploit to compromise the integrity of communications.
The technical flaw manifests in the hardcoded or shared cryptographic key implementation pattern that violates fundamental security principles outlined in cwe-310 and cwe-326. When the same private key is used across different customer environments, attackers who compromise one installation can easily leverage their knowledge of that key to impersonate other systems within the network. This vulnerability directly enables man-in-the-middle attacks by removing the cryptographic isolation that should exist between different customer deployments, allowing attackers to decrypt communications, inject malicious data, or perform session hijacking across multiple installations. The attack vector operates through the exploitation of weak key management practices that are categorized under attack technique t1566 in the ATT&CK framework.
The operational impact of this vulnerability extends beyond simple cryptographic weakness to encompass broader security implications for industrial control systems and network infrastructure. Organizations using affected Westermo WeOS devices face increased risk of unauthorized access, data breaches, and potential operational disruptions that could affect critical infrastructure. The shared key scenario creates a single point of failure where compromising one system provides attackers with access to multiple customer networks, amplifying the potential damage significantly. This vulnerability particularly affects environments where network security is paramount and where the integrity of communications between industrial devices and management systems is crucial for operational safety and business continuity.
Mitigation strategies for CVE-2015-7923 require immediate implementation of proper key management protocols and system updates to ensure unique cryptographic keys for each customer installation. Organizations should prioritize upgrading to Westermo WeOS version 4.19.0 or later, which addresses the shared key vulnerability through proper key generation and deployment mechanisms. Additional protective measures include implementing network segmentation to limit lateral movement, deploying intrusion detection systems to monitor for suspicious activities, and establishing robust key management processes that align with industry standards such as those defined in the NIST cybersecurity framework. The remediation process must also include thorough security assessments of existing deployments to identify any potential compromise and ensure that cryptographic keys are properly rotated and managed according to established security protocols.