CVE-2018-9086 in ThinkServer
Summary
by MITRE
In some Lenovo ThinkServer-branded servers, a command injection vulnerability exists in the BMC firmware download command. This allows a privileged user to download and execute arbitrary code inside the BMC. This can only be exploited by authorized privileged users.
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Analysis
by VulDB Data Team • 04/13/2020
The vulnerability identified as CVE-2018-9086 represents a critical command injection flaw within the Baseboard Management Controller (BMC) firmware of Lenovo ThinkServer servers. This vulnerability resides in the firmware download command processing mechanism, where insufficient input validation allows maliciously crafted commands to be executed within the BMC environment. The BMC serves as a dedicated management processor that provides out-of-band access to server hardware, making this vulnerability particularly concerning from a security perspective.
The technical nature of this flaw aligns with CWE-77 and CWE-94, representing command injection and code execution vulnerabilities respectively. The vulnerability specifically affects the BMC firmware download functionality where user-supplied parameters are not properly sanitized or validated before being processed. This allows an authenticated and privileged user to inject malicious commands that will be executed within the BMC context, potentially enabling arbitrary code execution. The attack vector requires prior authentication as the vulnerability is restricted to authorized privileged users, but this privilege escalation capability significantly expands the potential impact.
The operational impact of this vulnerability extends beyond traditional network security boundaries due to the BMC's role in server management and monitoring. Since the BMC operates independently from the main server OS and provides low-level hardware access, successful exploitation could allow attackers to gain complete control over the server's hardware management functions. This includes potential access to system configuration settings, firmware updates, power management controls, and other critical hardware-level operations. The vulnerability essentially provides a backdoor into the server's management interface that could be leveraged for persistent access or to facilitate further attacks within the network infrastructure.
Organizations should implement immediate mitigations including applying the vendor-provided firmware updates and patches released by Lenovo to address this vulnerability. Network segmentation of BMC management interfaces should be enforced to limit access to only authorized personnel. Additionally, monitoring and logging of BMC access activities should be implemented to detect any anomalous behavior or unauthorized access attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and execution through legitimate system tools, as attackers would leverage the legitimate BMC management interfaces to execute malicious code. Regular security assessments and vulnerability scanning should be conducted to identify similar flaws in other management controllers and firmware components within the server infrastructure.