CVE-2018-0406 in Web Security Appliance
Summary
by MITRE
A vulnerability in the web-based management interface of Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to conduct a reflected or Document Object Model based (DOM-based) 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 of an affected device. An attacker could exploit this vulnerability by persuading a user of the interface to click a crafted 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: CSCve84006.
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Analysis
by VulDB Data Team • 04/29/2023
The vulnerability identified as CVE-2018-0406 affects the web-based management interface of Cisco Web Security Appliance (WSA) devices, representing a critical security flaw that enables unauthenticated remote attackers to execute cross-site scripting attacks. This vulnerability specifically manifests as either a reflected XSS or DOM-based XSS attack vector, exploiting insufficient input validation mechanisms within the web interface. The flaw resides in the device's failure to properly sanitize user-supplied input, creating an attack surface that can be leveraged by malicious actors without requiring authentication credentials. The vulnerability was tracked under Cisco Bug ID CSCve84006, highlighting the specific nature of the input validation failure that enables this class of attack.
The technical implementation of this vulnerability stems from inadequate sanitization of parameters passed through the web interface, particularly those used in URL parameters or form inputs. When a user interacts with the management interface, the device fails to properly validate or escape user-supplied data before incorporating it into dynamic web content. This allows attackers to craft malicious URLs containing script payloads that, when clicked by an authenticated user, execute within the context of the victim's browser session. The reflected nature of the attack means that malicious input is reflected back to the user through the web application's response, while the DOM-based variant manipulates the document object model directly within the user's browser environment.
The operational impact of this vulnerability extends beyond simple script execution capabilities, as it provides attackers with the ability to access sensitive browser-based information and potentially escalate privileges within the web interface context. An attacker who successfully exploits this vulnerability could gain access to session cookies, user credentials, or other sensitive data stored within the browser's memory. The attack requires social engineering to convince a user to click a malicious link, but once executed, the consequences can be severe as the attacker operates within the trusted context of the authenticated user's session. This vulnerability represents a significant risk to organizations relying on WSA devices for web security management, as it undermines the integrity of the administrative interface and potentially exposes the entire web security infrastructure to unauthorized access.
Organizations should implement immediate mitigations including applying the latest security patches released by Cisco, which address the input validation deficiencies in the web interface. Network segmentation and access controls should be enhanced to limit exposure of the WSA management interface to trusted networks only. Web application firewalls can provide additional protection layers to detect and block malicious XSS payloads. Security monitoring should be enhanced to detect anomalous user behavior or unusual traffic patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-79 - Cross-site Scripting, which categorizes improper input validation as a primary root cause for XSS vulnerabilities. From an ATT&CK framework perspective, this represents a technique for Initial Access through Social Engineering followed by Execution of malicious code within the target environment, potentially leading to privilege escalation and lateral movement within the network infrastructure.