CVE-2020-5737 in Tenable.Sc
Summary
by MITRE
Stored XSS in Tenable.Sc before 5.14.0 could allow an authenticated remote attacker to craft a request to execute arbitrary script code in a user's browser session. Updated input validation techniques have been implemented to correct this issue.
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Analysis
by VulDB Data Team • 05/31/2024
The vulnerability identified as CVE-2020-5737 represents a critical stored cross-site scripting flaw within Tenable.Sc versions prior to 5.14.0. This security weakness resides in the application's handling of user input and demonstrates a classic stored XSS vulnerability pattern where malicious scripts are permanently stored on the server and executed whenever affected users access the compromised data. The vulnerability specifically affects authenticated attackers who can leverage their valid credentials to inject malicious code into the application's data storage mechanisms. This flaw operates under the Common Weakness Enumeration classification of CWE-79 which identifies improper neutralization of input during web page generation as a primary weakness. The attack vector requires an authenticated session, meaning that an attacker must first gain valid user credentials or exploit another authentication bypass mechanism to successfully execute this attack. The stored nature of this vulnerability means that the malicious payload persists within the application's database or storage systems, making it particularly dangerous as it can affect multiple users over time.
The technical implementation of this vulnerability allows an attacker to craft specific requests that, when processed by the vulnerable application, get stored in the system's backend storage. These stored requests contain malicious script code that executes automatically when other users view the affected content or interact with the compromised data. The vulnerability impacts the application's input validation mechanisms, which should have been filtering and sanitizing user-supplied data before storing it. The remediation implemented by Tenable in version 5.14.0 involved enhanced input validation techniques that properly sanitize and escape user input before it is stored or rendered in web responses. This fix aligns with the ATT&CK framework's technique T1566.001 which covers the use of malicious input to compromise applications. The vulnerability demonstrates how insufficient input validation can create persistent attack vectors that can be exploited by remote adversaries without requiring additional privileges beyond authentication. The stored XSS attack pattern is particularly concerning because it can be used to steal session cookies, perform unauthorized actions on behalf of users, or redirect victims to malicious sites.
The operational impact of CVE-2020-5737 extends beyond simple script execution as it represents a significant threat to user session integrity and data confidentiality within the Tenable.Sc environment. An attacker could potentially harvest sensitive information from authenticated user sessions, manipulate application functionality, or establish persistent access through session hijacking techniques. The vulnerability affects the application's security posture by creating a vector for privilege escalation and data exfiltration attacks. Organizations using affected versions of Tenable.Sc would be exposed to risks including unauthorized access to security scan results, configuration data, and potentially sensitive network information. The attack could be particularly damaging in enterprise environments where Tenable.Sc is used for vulnerability management and security monitoring, as it could enable attackers to compromise the security monitoring infrastructure itself. The remediation process requires careful deployment of the updated version 5.14.0 across all affected systems, including proper testing to ensure that the input validation changes do not inadvertently break legitimate functionality. Organizations should also consider implementing additional monitoring for suspicious input patterns and user activities that might indicate exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date security software and demonstrates how even authenticated attackers can leverage application flaws to achieve significant security breaches.