CVE-2018-7792 in Modicon M221
Summary
by MITRE
A Permissions, Privileges, and Access Control vulnerability exists in Schneider Electric's Modicon M221 product (all references, all versions prior to firmware V1.6.2.0). The vulnerability allows unauthorized users to decode the password using rainbow table.
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Analysis
by VulDB Data Team • 05/29/2026
The vulnerability identified as CVE-2018-7792 represents a critical permissions, privileges, and access control weakness within Schneider Electric's Modicon M221 industrial control device. This flaw affects all versions of the product prior to firmware revision V1.6.2.0, exposing a fundamental security gap in the device's authentication mechanism. The vulnerability specifically targets the password storage and verification process, creating an exploitable condition that undermines the device's security posture in industrial environments where access control is paramount.
The technical implementation of this vulnerability stems from inadequate password hashing mechanisms within the Modicon M221 firmware. Attackers can leverage rainbow table attacks to reverse engineer password hashes, effectively bypassing the authentication system without requiring legitimate credentials. This weakness directly violates the principle of least privilege and demonstrates a failure in proper cryptographic implementation. The vulnerability operates at the application layer of the device's security architecture, where user authentication credentials are processed and verified. According to CWE classification, this represents a weakness in cryptographic implementation, specifically CWE-327, which addresses the use of weak or broken cryptographic algorithms. The vulnerability creates a direct path for unauthorized access to industrial control systems, potentially enabling attackers to manipulate critical processes or gain persistent access to sensitive operational environments.
The operational impact of CVE-2018-7792 extends beyond simple unauthorized access, creating significant risks in industrial control environments where the Modicon M221 serves as a critical component in automation systems. An attacker exploiting this vulnerability could potentially gain administrative privileges to modify device configurations, access sensitive operational data, or disrupt industrial processes. This risk is particularly concerning given the industrial control system context where such devices often operate in critical infrastructure environments. The vulnerability enables attackers to perform lateral movement within networks and could potentially lead to more extensive compromise of industrial control systems. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and credential access methods, specifically leveraging the T1078 principle of valid accounts and T1550 for use of stolen credentials. The exposure of password hashes through rainbow table attacks represents a significant reduction in the attack surface required for successful exploitation.
Mitigation strategies for CVE-2018-7792 require immediate firmware updates to version V1.6.2.0 or later, which contain the necessary security patches to address the password hashing implementation. Organizations should also implement additional network segmentation measures to limit access to industrial control devices, ensuring that only authorized personnel can reach these critical systems. Security monitoring should be enhanced to detect unusual access patterns or authentication attempts that might indicate exploitation of this vulnerability. Network access controls should be implemented to restrict communication to these devices to trusted networks only, reducing the attack surface available to potential adversaries. The vulnerability highlights the importance of maintaining up-to-date firmware in industrial environments and demonstrates the necessity of proper cryptographic practices in embedded systems. Organizations should also conduct thorough security assessments of their industrial control infrastructure to identify similar vulnerabilities in other devices and systems that may be using weak cryptographic implementations or insecure password storage mechanisms.