CVE-2023-4855 in SMM
Summary
by MITRE • 04/15/2024
A command injection vulnerability was identified in SMM/SMM2 and FPC that could allow an authenticated user with elevated privileges to execute unauthorized commands via IPMI.
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Analysis
by VulDB Data Team • 04/15/2024
The command injection vulnerability identified in CVE-2023-4855 affects SMM/SMM2 and FPC firmware implementations that utilize IPMI (Intelligent Platform Management Interface) for remote system management. This vulnerability represents a critical security flaw that undermines the fundamental security model of firmware-based management systems. The issue stems from insufficient input validation and sanitization within the firmware's IPMI command processing mechanisms, creating a pathway for malicious actors to inject and execute arbitrary commands with elevated privileges. The vulnerability specifically targets the System Management Mode (SMM) execution environment where firmware operates with the highest privilege level, making it particularly dangerous as it can bypass traditional operating system security controls. The flaw exists in the firmware's handling of IPMI messages that are processed within the SMM context, where commands intended for legitimate management operations can be manipulated to execute unauthorized code sequences. This represents a sophisticated attack vector that exploits the inherent trust placed in firmware-based management interfaces while leveraging the elevated privileges that SMM execution provides.
The technical exploitation of this vulnerability occurs when an authenticated user with appropriate credentials accesses the IPMI interface and submits maliciously crafted commands that are not properly validated before execution. The injection occurs at the firmware level where IPMI commands are processed through SMM handlers, allowing attackers to manipulate command parameters or payloads that are subsequently executed in the privileged SMM context. This creates a direct pathway for privilege escalation and arbitrary code execution, as the firmware's SMM components operate with the same privileges as the system's core firmware and can access all system memory and hardware resources. The vulnerability manifests as a failure to properly sanitize user inputs within the firmware's IPMI command processing pipeline, enabling attackers to inject commands that are then executed with system-level privileges. According to CWE-77, this vulnerability maps directly to command injection flaws where untrusted data is incorporated into command execution without proper validation or escaping mechanisms. The attack requires authentication to the IPMI interface, but once authenticated, the attacker can leverage the elevated privileges inherent to SMM execution to perform actions that would otherwise be restricted.
The operational impact of CVE-2023-4855 extends far beyond typical software vulnerabilities, as it compromises the fundamental integrity of system management functions that are critical for enterprise and data center environments. Organizations relying on firmware-based management systems face potential complete system compromise, as the vulnerability allows attackers to execute arbitrary code with the highest privilege level available to the system. This could enable attackers to install persistent backdoors, modify system firmware, disable security features, or extract sensitive data from the system's memory and storage. The implications are particularly severe in data center environments where IPMI interfaces are commonly exposed to network access for remote management purposes, potentially allowing attackers to gain unauthorized access to entire server fleets. The vulnerability's impact is amplified by the fact that SMM operates outside of normal operating system security boundaries, making detection and prevention particularly challenging. According to ATT&CK framework, this vulnerability maps to T1059.007 (Command and Scripting Interpreter: PowerShell) and T1547.001 (Process Injection) as attackers could leverage the command injection to establish persistence and escalate privileges within the system management environment.
Mitigation strategies for CVE-2023-4855 require a multi-layered approach that addresses both the immediate vulnerability and broader security posture. Organizations should prioritize firmware updates from vendors that address this specific command injection flaw, as these updates typically include proper input validation and sanitization mechanisms within the IPMI processing pipeline. Network segmentation and access control should be implemented to restrict access to IPMI interfaces, limiting the attack surface by ensuring that only authorized management systems can access these interfaces. The principle of least privilege must be enforced by restricting IPMI access to only those users and systems that absolutely require it, while implementing strong authentication mechanisms including multi-factor authentication. Additionally, organizations should implement monitoring and logging of IPMI traffic to detect anomalous command sequences that may indicate exploitation attempts. The mitigation approach should also include regular firmware audits and vulnerability assessments to identify similar issues in other firmware components. Security teams should also consider implementing network-based intrusion detection systems that can monitor for suspicious IPMI command patterns and alert on potential exploitation attempts. The combination of these measures provides defense in depth against exploitation of this critical firmware vulnerability while maintaining operational functionality of the management interfaces.