CVE-2021-27459 in Rosemount X-STREAM Gas Analyzer
Summary
by MITRE • 05/21/2021
A vulnerability has been found in multiple revisions of Emerson Rosemount X-STREAM Gas Analyzer. The webserver of the affected products allows unvalidated files to be uploaded, which an attacker could utilize to execute arbitrary code.
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Analysis
by VulDB Data Team • 05/23/2021
The CVE-2021-27459 vulnerability represents a critical security flaw in Emerson Rosemount X-STREAM Gas Analyzer systems that operates at the intersection of web application security and industrial control systems. This vulnerability specifically affects multiple revisions of the gas analyzer platform, which is widely deployed in industrial environments for process monitoring and control. The affected devices incorporate a web server component that serves as the primary interface for system configuration and management, making it a prime target for attackers seeking to gain unauthorized access to critical industrial infrastructure. The vulnerability stems from insufficient input validation mechanisms within the file upload functionality of the web interface, creating a pathway for malicious actors to bypass security controls and introduce potentially harmful files into the system environment.
The technical implementation of this vulnerability aligns with CWE-434, which describes insecure file upload vulnerabilities where applications fail to properly validate file types, sizes, or contents before storing uploaded files. In the case of the X-STREAM Gas Analyzer, the web server component lacks proper validation checks that would normally prevent the upload of executable files or scripts. An attacker exploiting this vulnerability could upload malicious files such as web shells, executable binaries, or script files that would be executed with the privileges of the web server process. This unvalidated file upload mechanism creates a direct code execution vector that can be leveraged to establish persistent access to the industrial control system, potentially compromising the integrity of process monitoring data and operational procedures. The vulnerability's impact is amplified by the fact that these analyzers are typically deployed in critical infrastructure environments where system availability and data integrity are paramount.
The operational implications of CVE-2021-27459 extend beyond simple remote code execution to encompass broader industrial control system security concerns that align with ATT&CK technique T1190 for exploiting vulnerabilities in web applications. In industrial settings, the compromise of a gas analyzer system can lead to significant operational disruptions, including false readings that could trigger incorrect process responses, data manipulation that affects quality control, or complete system outages that impact production operations. The vulnerability also presents a risk of lateral movement within industrial networks, as compromised analyzers could serve as footholds for attackers seeking to access other connected systems. Organizations using these devices face potential regulatory compliance issues, particularly in industries governed by standards such as ISA/IEC 62443, which mandate secure configuration and operation of industrial control systems. The attack surface is further expanded by the fact that these devices often lack robust network segmentation controls, making them attractive targets for attackers seeking to establish persistent access to industrial networks.
Mitigation strategies for CVE-2021-27459 should focus on both immediate remediation and long-term security improvements within industrial environments. Organizations should prioritize applying vendor-provided patches and firmware updates as soon as they become available, while simultaneously implementing network segmentation to isolate affected systems from critical production networks. The implementation of web application firewalls and content filtering mechanisms can help detect and block malicious file uploads before they can be processed by the web server. Additionally, organizations should conduct thorough network assessments to identify all instances of affected equipment and establish monitoring procedures to detect suspicious file upload activities. Access controls should be strengthened through the implementation of least privilege principles, ensuring that only authorized personnel can access the web interface for these critical systems. The vulnerability also highlights the need for enhanced security awareness training for industrial control system operators and the establishment of secure configuration baselines that prevent unnecessary web server functionality from being enabled in production environments.