CVE-2017-3768 in IMM2
Summary
by MITRE
An unprivileged attacker with connectivity to the IMM2 could cause a denial of service attack on the IMM2 (Versions earlier than 4.4 for Lenovo System x and earlier than 6.4 for IBM System x). Flooding the IMM2 with a high volume of authentication failures via the Common Information Model (CIM) used by LXCA and OneCLI and other tools can exhaust available system memory which can cause the IMM2 to reboot itself until the requests cease.
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Analysis
by VulDB Data Team • 12/28/2019
The vulnerability identified as CVE-2017-3768 represents a significant denial of service weakness within the Integrated Management Module version 2 (IMM2) found in Lenovo and IBM System x servers. This flaw specifically affects systems running IMM2 firmware versions earlier than 4.4 for Lenovo systems and earlier than 6.4 for IBM systems, creating a critical operational risk for enterprise environments that rely on these management interfaces for system monitoring and maintenance. The vulnerability stems from insufficient input validation and resource management within the CIM (Common Information Model) authentication mechanisms that are utilized by various management tools including LXCA (Lenovo XClarity Administrator) and OneCLI.
The technical exploitation of this vulnerability occurs through a straightforward yet effective method of flooding the IMM2 with excessive authentication failure requests. An unprivileged attacker who can establish network connectivity to the IMM2 interface can systematically submit numerous invalid authentication attempts through the CIM protocol interface. This malicious activity overwhelms the system's memory resources as each failed authentication attempt consumes memory allocation for processing and logging purposes. The IMM2's failure handling mechanism does not adequately implement rate limiting or resource exhaustion protection, allowing the accumulation of failed authentication states to eventually deplete available memory resources. The system's response to this resource exhaustion is a complete reboot cycle, effectively rendering the management interface unavailable and disrupting normal system operations.
The operational impact of this vulnerability extends beyond simple service disruption as it fundamentally compromises the availability of critical system management functions. When the IMM2 reboots due to memory exhaustion, administrators lose access to remote management capabilities including hardware monitoring, firmware updates, and system diagnostics that are essential for maintaining enterprise server infrastructure. This vulnerability particularly affects data center environments where IMM2 interfaces are crucial for centralized system management and monitoring operations. The reboot cycles can occur repeatedly if the attack continues, potentially causing extended downtime and requiring manual intervention to restore management access. The attack vector is particularly concerning as it requires minimal privileges and can be executed from any network location that can reach the IMM2 interface, making it accessible to a wide range of potential attackers.
Mitigation strategies for CVE-2017-3768 should focus on both immediate defensive measures and long-term firmware upgrades. Organizations should implement network segmentation and access controls to limit connectivity to IMM2 interfaces, restricting access to trusted management networks only. Network-level rate limiting and firewall rules can help prevent excessive authentication attempts from overwhelming the system. Additionally, administrators should deploy monitoring solutions to detect unusual authentication patterns that may indicate exploitation attempts. The most effective long-term solution involves upgrading IMM2 firmware to versions 4.4 or later for Lenovo systems and 6.4 or later for IBM systems, which contain fixes addressing the memory exhaustion vulnerability. This vulnerability aligns with CWE-400, which describes unrestricted resource consumption, and maps to ATT&CK technique T1499.004 for Denial of Service, highlighting the importance of proper resource management and authentication handling in system security design.