CVE-2018-0091 in Identity Services Engine
Summary
by MITRE
A vulnerability in the web-based management interface of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to conduct a Document Object Model (DOM) cross-site scripting (XSS) attack against a user of the web-based management interface of an affected device. The vulnerability is due to insufficient validation of user-supplied input by the web-based management interface. An attacker could exploit this vulnerability by persuading a user of the interface to click a malicious link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the interface or allow the attacker to access sensitive browser-based information. Cisco Bug IDs: CSCvf73922.
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Analysis
by VulDB Data Team • 02/01/2021
The vulnerability identified as CVE-2018-0091 affects Cisco Identity Services Engine (ISE) web-based management interface, representing a critical security flaw that undermines the integrity of the system's user authentication and session management mechanisms. This issue resides within the web interface's input validation controls, where insufficient sanitization of user-supplied data creates an exploitable entry point for malicious actors. The vulnerability specifically manifests as a DOM-based cross-site scripting flaw that operates entirely within the browser environment rather than server-side, making it particularly challenging to detect and mitigate through traditional network security measures.
The technical exploitation of this vulnerability occurs through a carefully crafted malicious link that, when clicked by an authenticated user within the web interface, triggers the execution of arbitrary JavaScript code in the victim's browser context. This DOM-based XSS attack leverages the insufficient input validation mechanisms that should have filtered and sanitized all user-supplied data before processing. The vulnerability falls under CWE-79 which specifically addresses Cross-site Scripting flaws, and more precisely aligns with CWE-937 which covers the execution of arbitrary code through DOM manipulation. The attack vector requires social engineering to convince users to click malicious links, but once executed, the attack operates entirely within the browser without requiring additional authentication or network access from the attacker.
The operational impact of this vulnerability extends beyond simple script execution to potentially enable complete session hijacking and credential theft, as attackers can access sensitive browser-based information and manipulate the user's interaction with the ISE management interface. This flaw essentially allows attackers to perform actions as if they were the legitimate user, potentially gaining access to privileged management functions and sensitive network configuration data. The vulnerability's remote and unauthenticated nature means that attackers can exploit it without requiring physical access or prior network credentials, making it particularly dangerous in environments where the ISE management interface is accessible from untrusted networks or exposed to external traffic.
Security professionals should implement multiple layers of defense to mitigate this vulnerability, beginning with immediate patching of affected systems to address the root cause of insufficient input validation. Network segmentation and access controls should be strengthened to limit exposure of the ISE management interface to trusted networks only, while implementing web application firewalls to detect and block malicious payloads. Browser security policies should be enhanced through the implementation of Content Security Policy headers and the use of secure coding practices that prevent DOM-based XSS attacks. The vulnerability also highlights the importance of regular security assessments and penetration testing of web interfaces to identify similar input validation flaws that could be exploited through various attack vectors including those mapped to the ATT&CK framework's T1059.007 technique for command and scripting interpreter execution, where attackers leverage browser-based scripting to execute malicious code within the victim's browser environment.