CVE-2018-15403 in Emergency Responder
Summary
by MITRE
A vulnerability in the web interface of Cisco Emergency Responder, Cisco Unified Communications Manager, Cisco Unified Communications Manager IM & Presence Service, and Cisco Unity Connection could allow an authenticated, remote attacker to redirect a user to a malicious web page. The vulnerability is due to improper input validation of the parameters of an HTTP request. An attacker could exploit this vulnerability by crafting an HTTP request that causes the web interface to redirect a request to a specific malicious URL. This type of vulnerability is known as an open redirect attack and is used in phishing attacks that get users to unknowingly visit malicious sites.
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Analysis
by VulDB Data Team • 05/22/2023
The vulnerability identified as CVE-2018-15403 represents a critical security flaw in Cisco's enterprise communication platforms including Emergency Responder, Unified Communications Manager, IM & Presence Service, and Unity Connection. This issue stems from inadequate input validation mechanisms within the web interface components of these systems, creating an avenue for malicious actors to manipulate HTTP request parameters. The vulnerability specifically affects the authentication handling processes where legitimate user sessions can be exploited to redirect users to attacker-controlled domains without proper validation of destination URLs.
This weakness falls under the CWE-601 category of Open Redirect vulnerabilities, which occur when web applications fail to properly validate redirect URLs, allowing attackers to craft malicious requests that redirect users to phishing sites or malicious content. The flaw operates at the application layer of the OSI model, specifically within the web interface components that handle user authentication and session management. Attackers can exploit this by constructing specially crafted HTTP requests that contain malicious redirect parameters, which the vulnerable systems will process without sufficient validation checks.
The operational impact of this vulnerability is significant as it enables sophisticated phishing campaigns that can bypass user awareness and traditional security controls. When authenticated users interact with the vulnerable web interface, they become unwitting participants in attacks where their browsers redirect them to malicious domains that can harvest credentials, deploy malware, or conduct further social engineering operations. The attack vector requires only an authenticated session, making it particularly dangerous as it can be leveraged by insiders or compromised accounts. This vulnerability directly maps to ATT&CK technique T1566.001 which covers "Phishing: Spearphishing Attachment" and T1566.002 which addresses "Phishing: Spearphishing Link", both of which rely on user redirection to achieve their objectives.
Organizations affected by this vulnerability face substantial risk of credential theft, data exfiltration, and potential lateral movement within their networks. The open redirect mechanism can be combined with other attack vectors to create more sophisticated phishing campaigns where users are directed to seemingly legitimate Cisco interface pages that then redirect to malicious sites. Mitigation strategies should include implementing strict URL validation controls, disabling unnecessary redirect functionality where possible, and deploying network-level controls to monitor and block suspicious redirect patterns. Cisco has released patches and updates to address this vulnerability, and organizations should prioritize immediate remediation to protect their communication infrastructure from exploitation attempts.