CVE-2019-0054 in Junos
Summary
by MITRE
An Improper Certificate Validation weakness in the SRX Series Application Identification (app-id) signature update client of Juniper Networks Junos OS allows an attacker to perform Man-in-the-Middle (MitM) attacks which may compromise the integrity and confidentiality of the device. This issue affects: Juniper Networks Junos OS 15.1X49 versions prior to 15.1X49-D120 on SRX Series devices. No other versions of Junos OS are affected.
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Analysis
by VulDB Data Team • 01/05/2024
The vulnerability CVE-2019-0054 represents a critical improper certificate validation flaw within the SRX Series Application Identification (app-id) signature update client of Juniper Networks Junos OS. This weakness specifically impacts devices running Junos OS version 15.1X49 prior to 15.1X49-D120 on SRX Series hardware. The vulnerability stems from inadequate certificate validation mechanisms that fail to properly verify the authenticity and integrity of digital certificates used during the application signature update process. This flaw creates a significant security gap that allows malicious actors to intercept and manipulate communications between the device and the update servers. The vulnerability aligns with CWE-295, which specifically addresses improper certificate validation, and represents a direct threat to the security posture of affected network infrastructure. The issue is particularly concerning because it undermines the trust model that should exist between network devices and their update mechanisms, potentially allowing attackers to establish false trust relationships.
The technical implementation of this vulnerability occurs within the app-id signature update client component of the Junos OS operating system. When the SRX Series device attempts to download application identification signatures from Juniper's update servers, the device fails to properly validate the server certificates presented during the TLS handshake process. This validation failure can be exploited through man-in-the-middle attacks where an attacker positioned between the device and the update server can present a fraudulent certificate. The attacker can then intercept and modify the signature updates, potentially introducing malicious signatures that could compromise network traffic monitoring and classification capabilities. The attack vector specifically targets the secure update mechanism that should ensure the integrity of application identification rules. This weakness enables attackers to manipulate the device's understanding of network applications, potentially leading to bypass of security controls or misclassification of traffic. The vulnerability operates at the transport layer security validation level, making it particularly dangerous as it undermines the fundamental security assumptions of the update process.
The operational impact of CVE-2019-0054 extends beyond simple data interception, as it fundamentally compromises the integrity and confidentiality of network device operations. When exploited, this vulnerability allows attackers to modify application identification signatures that are critical for network security policy enforcement and traffic classification. The compromised device may begin misclassifying network traffic, potentially allowing malicious activities to bypass security controls or be incorrectly flagged as legitimate traffic. This can lead to significant operational disruptions where network administrators lose confidence in their security monitoring capabilities. The vulnerability also creates opportunities for attackers to perform persistent threats by injecting malicious signatures that could remain undetected for extended periods. The impact is particularly severe for organizations relying on SRX Series devices for application-aware security policies, as the compromise of signature updates can effectively neutralize application control measures. This vulnerability directly impacts the CIA triad, specifically compromising both integrity and confidentiality of device operations and network traffic analysis.
Organizations affected by CVE-2019-0054 should immediately implement mitigation strategies focusing on the specific affected versions of Junos OS. The primary recommendation is to upgrade to Junos OS version 15.1X49-D120 or later, which contains the necessary certificate validation fixes. Network administrators should also consider implementing additional monitoring for suspicious update activities and certificate-related events on affected devices. The vulnerability's exploitation requires network access and positioning between the device and update servers, making network segmentation and access controls important defensive measures. Organizations should also review their application identification policies to ensure they have adequate detection mechanisms for signature tampering. From an ATT&CK perspective, this vulnerability maps to T1071.004 (Application Layer Protocol: DNS) and T1566 (Phishing) as attackers could leverage modified signatures to redirect traffic or establish false trust relationships. The remediation process should include comprehensive testing of the updated firmware to ensure that the certificate validation improvements function correctly without disrupting existing network operations. Security teams should also implement continuous monitoring for any signs of compromise, as the vulnerability could potentially allow attackers to maintain persistence through manipulated signature updates.