CVE-2018-9073 in Chassis Management Module
Summary
by MITRE
Lenovo Chassis Management Module (CMM) prior to version 2.0.0 utilizes a hardcoded encryption key to protect certain secrets. Possession of the key can allow an attacker that has already compromised the server to decrypt these secrets.
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Analysis
by VulDB Data Team • 04/13/2020
The Lenovo Chassis Management Module represents a critical component in enterprise server infrastructure providing out-of-band management capabilities through the chassis management controller. This module serves as a separate subsystem responsible for monitoring hardware status, managing power states, and handling remote administration tasks. The vulnerability stems from the implementation of a hardcoded encryption key within the CMM firmware versions prior to 2.0.0, which violates fundamental security principles outlined in CWE-327. The presence of such a static key creates a persistent weakness that can be exploited by attackers who have already gained access to the server environment, as the key remains constant across all affected systems and can be discovered through reverse engineering or memory analysis techniques.
The technical flaw manifests in the cryptographic implementation where the CMM employs a fixed encryption key for protecting sensitive secrets stored within the system. This approach fundamentally undermines the security model since the same key is used across multiple devices, making it vulnerable to exploitation once discovered. Attackers who have already compromised the server environment can extract this hardcoded key from memory or firmware components, subsequently using it to decrypt confidential information such as administrator credentials, system configuration details, or other sensitive data that was previously protected by the encryption mechanism. This vulnerability aligns with ATT&CK technique T1552.001 for Unsecured Credentials and T1003.002 for OS Credential Dumping, as it enables attackers to access previously protected secrets.
The operational impact of this vulnerability extends beyond simple credential theft, as it compromises the integrity of the entire server management infrastructure. When an attacker gains access to the hardcoded key, they can potentially escalate privileges within the management domain, manipulate system configurations, or extract additional sensitive information from other components that rely on the same encryption scheme. The vulnerability affects organizations using older Lenovo server models that incorporate the affected CMM firmware, potentially exposing critical infrastructure to unauthorized access and manipulation. This weakness particularly impacts enterprise environments where server management security is paramount, as it creates a persistent backdoor that remains active across all affected systems regardless of other security controls implemented.
Organizations should immediately update their Lenovo server firmware to version 2.0.0 or later to address this vulnerability, as the patch resolves the hardcoded key issue by implementing proper key management procedures. System administrators should conduct thorough inventory assessments to identify all affected servers and ensure timely deployment of the security update. Additionally, implementing network segmentation and access controls around management interfaces can help limit the impact if an attacker does gain access to the system. The vulnerability highlights the importance of proper cryptographic key management practices as outlined in NIST SP 800-57 and aligns with the principle of least privilege, where hardcoded credentials should never be used in production environments. Regular security assessments and firmware monitoring should be implemented to prevent similar issues in the future, ensuring that all cryptographic implementations follow established security best practices and avoid the pitfalls of static key usage.