CVE-2019-6859 in Controller
Summary
by MITRE
A CWE-798: Use of Hardcoded Credentials vulnerability exists in Modicon Controllers (All versions of the following CPUs and Communication Module product references listed in the Security Notifications), which could cause the disclosure of FTP hardcoded credentials when using the Web server of the controller on an unsecure network.Ê
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Analysis
by VulDB Data Team • 06/01/2024
The vulnerability identified as CVE-2019-6859 represents a critical security flaw categorized under CWE-798, which specifically addresses the use of hardcoded credentials in software systems. This vulnerability affects Modicon Controllers across all versions of their CPU and Communication Module product lines, as documented in official security notifications. The flaw manifests when these industrial control systems utilize their built-in web server functionality over unsecured network connections, creating a significant exposure vector for unauthorized parties.
The technical implementation of this vulnerability involves the embedding of hardcoded FTP credentials directly into the controller firmware or software code. When the web server component is active and accessible over the network, these hardcoded credentials become discoverable through various reconnaissance techniques. Attackers can exploit this weakness by accessing the controller's web interface without requiring additional authentication mechanisms, effectively bypassing normal security controls. The hardcoded nature of these credentials means they cannot be changed or updated through standard operational procedures, rendering the system perpetually vulnerable once deployed.
The operational impact of CVE-2019-6859 extends beyond simple credential disclosure, as it creates a persistent backdoor access mechanism for malicious actors. Industrial control systems running affected Modicon controllers become vulnerable to unauthorized access, potentially enabling attackers to modify system configurations, access sensitive operational data, or even manipulate industrial processes. This vulnerability particularly threatens environments where industrial networks are not properly segmented or where network monitoring is insufficient, as the hardcoded credentials provide a consistent method for gaining unauthorized access regardless of network security measures.
Organizations should implement immediate mitigations including network segmentation to isolate affected controllers from untrusted networks, disabling unnecessary web server functionality when not required, and implementing robust network monitoring to detect unauthorized access attempts. The vulnerability aligns with ATT&CK technique T1078.004, which covers legitimate credentials obtained through default credentials, and represents a significant concern for industrial control systems following the principles outlined in NIST SP 800-82 for industrial control system security. Regular security assessments and firmware updates should be implemented to address this and similar hardcoded credential vulnerabilities in industrial environments.