CVE-2021-33021 in SCADA
Summary
by MITRE • 05/16/2022
xArrow SCADA versions 7.2 and prior is vulnerable to cross-site scripting due to parameter ‘edate’ of the resource xhisalarm.htm, which may allow an unauthorized attacker to execute arbitrary code.
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Analysis
by VulDB Data Team • 05/18/2022
The xArrow SCADA system version 7.2 and earlier presents a critical cross-site scripting vulnerability through the 'edate' parameter within the xhisalarm.htm resource. This flaw represents a significant security weakness in industrial control systems that could enable unauthorized attackers to inject malicious scripts into web interfaces. The vulnerability stems from inadequate input validation and sanitization mechanisms within the SCADA software's web-based administrative interface, creating an attack surface that adversaries can exploit to compromise system integrity and potentially disrupt critical operations.
This vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws in web applications. The 'edate' parameter in the xhisalarm.htm resource fails to properly sanitize user-supplied input, allowing attackers to inject malicious JavaScript code that executes in the context of other users' browsers. The attack vector specifically targets the SCADA system's web interface where operators and administrators interact with historical alarm data, making it particularly dangerous as it could be exploited during routine system monitoring activities. The vulnerability's impact extends beyond simple script execution as it could potentially enable attackers to escalate privileges, access sensitive operational data, or manipulate system configurations.
The operational implications of this vulnerability are severe for industrial environments relying on xArrow SCADA systems. Attackers could leverage this XSS flaw to perform session hijacking, steal administrative credentials, or redirect users to malicious sites that could further compromise the industrial control network. The potential for executing arbitrary code through this vector means that attackers could gain persistent access to the SCADA system, potentially leading to disruption of critical infrastructure operations or even physical damage to industrial processes. The vulnerability's presence in the historical alarm display functionality suggests that attackers could manipulate alarm data to obscure genuine system issues or create false alerts that could mislead operators during critical situations.
From an ATT&CK framework perspective, this vulnerability maps to multiple techniques including T1566 for social engineering through web-based attacks and T1059 for command and control through script injection. The attack chain typically begins with reconnaissance to identify the vulnerable SCADA system, followed by crafting malicious payloads targeting the 'edate' parameter, and concludes with successful execution of malicious scripts in victim browsers. Mitigation strategies should include immediate deployment of vendor patches, implementation of web application firewalls, and strict input validation controls. Organizations should also conduct comprehensive security assessments of their SCADA environments, implement network segmentation to isolate critical systems, and establish robust monitoring procedures to detect anomalous web traffic patterns that might indicate exploitation attempts. The vulnerability underscores the critical importance of securing industrial control system interfaces and maintaining up-to-date security measures to protect against increasingly sophisticated cyber threats targeting operational technology environments.