CVE-2018-5441 in mGuard
Summary
by MITRE
An Improper Validation of Integrity Check Value issue was discovered in PHOENIX CONTACT mGuard firmware versions 7.2 to 8.6.0. mGuard devices rely on internal checksums for verification of the internal integrity of the update packages. Verification may not always be performed correctly, allowing an attacker to modify firmware update packages.
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Analysis
by VulDB Data Team • 12/31/2019
The vulnerability identified as CVE-2018-5441 represents a critical weakness in the PHOENIX CONTACT mGuard security appliance firmware ecosystem, specifically affecting versions 7.2 through 8.6.0. This issue falls under the broader category of improper validation of integrity check values, which is categorized as CWE-347 within the Common Weakness Enumeration framework. The mGuard devices operate as industrial security appliances designed to protect critical infrastructure networks, making this vulnerability particularly concerning from a cybersecurity perspective. The affected firmware implementations demonstrate a fundamental flaw in how cryptographic integrity checks are validated during firmware update processes, creating a potential attack vector that could compromise the entire security infrastructure of industrial environments.
The technical flaw manifests in the firmware's reliance on internal checksum mechanisms that are supposed to verify the integrity of update packages before installation. However, the validation process contains a critical implementation error that allows attackers to bypass these integrity checks through manipulation of update packages. This vulnerability stems from insufficient validation of checksum values during the firmware update process, creating a scenario where malicious actors can modify firmware images without detection. The flaw specifically affects the verification logic that should ensure update packages remain untampered throughout the distribution and installation phases, enabling attackers to inject malicious code or alter functionality within the device firmware. This represents a classic case of weak cryptographic validation where the system fails to properly authenticate update integrity, allowing for potential supply chain attacks or insider threat exploitation.
The operational impact of this vulnerability extends beyond simple firmware modification capabilities, as it fundamentally undermines the security model of industrial control systems that rely on mGuard appliances for network protection. Attackers who successfully exploit this vulnerability could potentially gain unauthorized access to industrial networks, modify security policies, or establish persistent backdoors within critical infrastructure environments. The implications are particularly severe given that mGuard devices are commonly deployed in industrial settings where network security is paramount for operational continuity and safety. The vulnerability creates a persistent threat vector that could allow attackers to compromise the integrity of security controls, potentially leading to system outages, data breaches, or even physical safety risks in environments where industrial automation systems are critical to operations. This weakness directly impacts the CIA triad, particularly compromising the integrity and availability of security systems that organizations depend upon for protection.
Organizations affected by this vulnerability should immediately implement mitigation strategies focused on strengthening firmware update processes and network segmentation. The primary recommendation involves implementing robust cryptographic verification mechanisms that properly validate integrity check values before any firmware installation occurs. Security teams should also consider deploying network monitoring solutions to detect anomalous update activities or unauthorized modifications to device configurations. Additionally, implementing strict access controls and network segmentation around mGuard devices can help limit the potential impact of exploitation. The remediation process should include updating to firmware versions that address the integrity validation flaw, while also establishing comprehensive audit procedures to verify the authenticity of all firmware updates. Organizations should also consider implementing secure boot mechanisms and hardware-based security features that can provide additional layers of protection against firmware-level attacks. This vulnerability highlights the critical importance of proper cryptographic implementation in industrial security devices and serves as a reminder of the need for robust integrity validation in all firmware update processes.