CVE-2020-15307 in Guardian
Summary
by MITRE
Nozomi Guardian before 19.0.4 allows attackers to achieve stored XSS (in the web front end) by leveraging the ability to create a custom field with a crafted field name.
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Analysis
by VulDB Data Team • 07/01/2020
The vulnerability identified as CVE-2020-15307 affects Nozomi Guardian versions prior to 19.0.4 and represents a critical stored cross-site scripting flaw that can be exploited by attackers to compromise the web front end of the system. This vulnerability specifically arises from insufficient input validation and sanitization mechanisms within the custom field creation functionality of the application. Attackers can leverage this weakness by crafting malicious field names that contain embedded malicious scripts, which then get stored within the application's database and subsequently executed when other users view the custom fields in the web interface. The stored nature of this XSS vulnerability means that the malicious payload persists in the system and can affect multiple users over time rather than requiring a specific moment of interaction. This flaw falls under the CWE-79 category of Cross-Site Scripting, which is classified as a common weakness in web applications where user-controllable data is not properly sanitized before being rendered back to users. The vulnerability demonstrates a fundamental failure in the application's security architecture to properly validate and sanitize user input, particularly in areas where administrators or users can define custom data fields within the system. The impact extends beyond simple script execution as it can potentially allow attackers to steal session cookies, perform unauthorized actions on behalf of victims, redirect users to malicious sites, or even escalate privileges within the application environment.
The operational implications of this vulnerability are severe as it provides attackers with a persistent foothold within the Nozomi Guardian environment that can be leveraged for extended reconnaissance and attack phases. When an attacker successfully crafts a malicious custom field name, the stored XSS payload becomes active whenever any user accesses the affected interface, making it particularly dangerous in multi-user environments where different personnel interact with the system. The vulnerability can be exploited through various attack vectors including social engineering techniques where attackers convince legitimate users to create custom fields with malicious content, or through direct exploitation if the attacker has access to create custom fields within the application. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.005 for Command and Scripting Interpreter, as attackers can execute arbitrary scripts through the XSS payload. The persistence of the vulnerability means that even after the initial attack, the malicious scripts remain active and can be used for ongoing monitoring or further exploitation of the system. Organizations using vulnerable versions of Nozomi Guardian face significant risks including potential data exfiltration, unauthorized access to sensitive monitoring information, and possible lateral movement within their network infrastructure. The vulnerability also represents a failure in the principle of least privilege, as it allows users with the ability to create custom fields to potentially escalate their privileges or compromise other users within the system.
Mitigation strategies for CVE-2020-15307 should focus on immediate remediation through upgrading to Nozomi Guardian version 19.0.4 or later, which includes proper input validation and sanitization mechanisms for custom field names. Organizations should implement comprehensive input sanitization measures that filter out potentially malicious content including script tags, event handlers, and other XSS payload indicators from user-controllable input fields. The implementation of Content Security Policy headers can provide additional defense-in-depth measures to prevent execution of unauthorized scripts even if the primary vulnerability is not fully patched. Regular security assessments and input validation testing should be conducted to identify similar vulnerabilities in other application components. Access controls should be reviewed to limit the ability to create custom fields to only trusted administrative users, reducing the attack surface for this type of vulnerability. Network monitoring should be enhanced to detect unusual field creation patterns or attempts to inject malicious content into the system. Organizations should also consider implementing web application firewalls to detect and block suspicious input patterns that may indicate attempts to exploit XSS vulnerabilities. The vulnerability underscores the importance of proper security testing during application development, particularly in areas where user input is processed and stored for later retrieval. Regular security training for administrators and developers should emphasize the importance of input validation and the potential consequences of insufficient sanitization of user-controllable data. Incident response procedures should be updated to include detection and response protocols for stored XSS vulnerabilities, ensuring that organizations can quickly identify and remediate similar issues in their environment.