CVE-2019-1866 in Webex Business Suite
Summary
by MITRE
Cisco Webex Business Suite before 39.1.0 contains a vulnerability that could allow an unauthenticated, remote attacker to affect the integrity of the application. The vulnerability is due to improper validation of host header values. An attacker with a privileged network position, either a man-in-the-middle or by intercepting wireless network traffic, could exploit this vulnerability to manipulate header values sent by a client to the affected application. The attacker could cause the application to use input from the header to redirect a user from the Cisco Webex Meetings Online site to an arbitrary site of the attacker's choosing.
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Analysis
by VulDB Data Team • 04/14/2020
The vulnerability identified as CVE-2019-1866 affects Cisco Webex Business Suite versions prior to 39.1.0, presenting a critical security flaw that compromises application integrity through improper host header validation. This weakness stems from the application's failure to adequately validate host header values received from client requests, creating an avenue for malicious manipulation of HTTP headers. The vulnerability operates under the CWE-20 category, specifically addressing improper input validation, which falls within the broader scope of injection flaws that can lead to various security consequences including unauthorized redirects and session manipulation. The attack vector requires an attacker to occupy a privileged network position, typically achieved through man-in-the-middle attacks or by intercepting wireless network traffic, making this vulnerability particularly concerning in environments where network security is compromised.
The technical exploitation of this vulnerability enables attackers to manipulate HTTP host headers in a manner that allows arbitrary redirection of users from legitimate Cisco Webex Meetings Online sites to attacker-controlled destinations. This host header injection vulnerability specifically targets the application's trust in client-provided header values without proper sanitization or validation. When the application processes these unvalidated headers, it can be tricked into constructing redirects that point to malicious domains controlled by the attacker. The operational impact extends beyond simple redirection as it can facilitate phishing attacks, credential theft, and further exploitation of user trust in the legitimate Cisco Webex platform. The vulnerability essentially allows attackers to hijack user sessions and redirect them to malicious sites that appear to be legitimate Cisco Webex interfaces, creating a sophisticated social engineering attack vector.
The security implications of CVE-2019-1866 align with ATT&CK framework techniques including T1566 for Phishing and T1190 for Exploit Public-Facing Application, demonstrating how this vulnerability can serve as an entry point for broader attack campaigns. The affected application's reliance on potentially malicious host header values creates a trust boundary violation that can be leveraged to compromise user sessions and potentially gain access to sensitive corporate communications. Organizations utilizing Cisco Webex Business Suite versions before 39.1.0 face significant risk of credential compromise and data exfiltration through this vulnerability, particularly in environments where network traffic interception is possible. The vulnerability's impact is amplified by the widespread use of Webex for business communications, making successful exploitation potentially devastating for enterprise security posture.
Mitigation strategies for CVE-2019-1866 require immediate implementation of Cisco's security advisory patches and updates to version 39.1.0 or later, which address the host header validation issues through proper input sanitization and validation mechanisms. Network administrators should implement strict host header validation at network boundaries and consider deploying web application firewalls to monitor and filter suspicious header values. Organizations should also conduct comprehensive security assessments to identify any other applications that may be vulnerable to similar host header injection attacks, as this class of vulnerability is commonly found in web applications. Additional protective measures include implementing strict access controls, monitoring network traffic for anomalous header values, and educating users about the risks of phishing attacks that may exploit this vulnerability. The remediation process should also involve reviewing and strengthening the application's security configuration to prevent future occurrences of improper input validation that could lead to similar security flaws.