CVE-2014-5340 in Check Mk
Summary
by MITRE
The wato component in Check_MK before 1.2.4p4 and 1.2.5 before 1.2.5i4 uses the pickle Python module unsafely, which allows remote attackers to execute arbitrary code via a crafted serialized object, related to an automation URL.
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Analysis
by VulDB Data Team • 03/28/2022
The vulnerability identified as CVE-2014-5340 affects the wato component within Check_MK monitoring software versions prior to 1.2.4p4 and 1.2.5i4. This represents a critical security flaw that stems from the unsafe usage of Python's pickle module, creating a remote code execution vector that can be exploited by attackers without authentication. The vulnerability specifically manifests through an automation URL that processes serialized objects, making it particularly dangerous in networked environments where the monitoring system is exposed to external traffic. The wato component serves as the web-based configuration interface for Check_MK, which is widely used for network and system monitoring across enterprise environments, making this vulnerability particularly impactful for organizations relying on this monitoring infrastructure.
The technical root cause of this vulnerability lies in the improper handling of serialized data within the pickle module, which is inherently unsafe when processing untrusted input. The pickle module in Python is designed for serializing and deserializing Python objects, but it executes arbitrary code during the deserialization process. When the wato component processes automation URLs that contain serialized objects, it fails to validate or sanitize the input before passing it to pickle for deserialization. This creates a classic deserialization vulnerability where an attacker can craft malicious serialized objects that, when processed, execute arbitrary commands on the target system with the privileges of the Check_MK service account. The vulnerability maps directly to CWE-502, which specifically addresses Deserialization of Untrusted Data, and falls under the broader category of insecure deserialization flaws that have been extensively documented in security literature and frameworks like the OWASP Top Ten.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with complete control over the affected monitoring system. An attacker who successfully exploits this vulnerability could gain access to sensitive monitoring data, manipulate system configurations, disable monitoring alerts, or use the compromised system as a pivot point for further attacks within the network. Since Check_MK systems are often deployed in critical infrastructure environments and may be accessible from multiple network segments, the potential for lateral movement and data exfiltration increases significantly. The vulnerability also affects the integrity and availability of the monitoring infrastructure, potentially leading to undetected intrusions or false security alerts that could mask ongoing attacks. Organizations using Check_MK in production environments face serious operational risks, as the compromise of a monitoring system can result in delayed incident response and reduced visibility into network activities, making it harder to detect and respond to security incidents.
Organizations should immediately apply the available patches for Check_MK versions 1.2.4p4 and 1.2.5i4 to remediate this vulnerability, as no effective workarounds exist for the pickle module usage pattern. The patch implementation should be prioritized in environments where Check_MK is exposed to untrusted networks or where the automation URLs are accessible from external systems. Security teams should also implement network segmentation to limit access to the wato component and monitor for suspicious automation URL requests that could indicate exploitation attempts. Additional mitigations include disabling unused automation features, implementing strict access controls for the monitoring interface, and conducting thorough vulnerability assessments of other Python applications within the environment that might be similarly vulnerable to pickle-based attacks. This vulnerability demonstrates the importance of proper input validation and the dangers of using unsafe serialization mechanisms in web applications, aligning with ATT&CK technique T1059.006 for Command and Scripting Interpreter and T1210 for Exploitation of Remote Services, both of which are commonly used by attackers to establish persistence and escalate privileges in compromised environments.