CVE-2019-15987 in Webex Event Center
Summary
by MITRE
A vulnerability in web interface of the Cisco Webex Event Center, Cisco Webex Meeting Center, Cisco Webex Support Center, and Cisco Webex Training Center could allow an unauthenticated, remote attacker to guess account usernames. The vulnerability is due to missing CAPTCHA protection in certain URLs. An attacker could exploit this vulnerability by sending a crafted request to the web interface. A successful exploit could allow the attacker to know if a given username is valid and find the real name of the user.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 02/28/2024
This vulnerability exists within the web interface components of Cisco Webex platforms including Event Center, Meeting Center, Support Center, and Training Center. The flaw represents a significant information disclosure issue that undermines the security posture of these collaboration platforms. The vulnerability stems from the absence of CAPTCHA protection mechanisms on specific URLs that handle user authentication or account validation processes. This design oversight creates an attack surface where malicious actors can systematically enumerate valid user accounts through automated means.
The technical implementation of this vulnerability allows attackers to exploit the lack of rate limiting and validation controls in the web interface. When an attacker sends a crafted request to the vulnerable URLs, the system responds in a manner that differentiates between valid and invalid usernames. This differential response behavior enables account enumeration attacks where attackers can determine which usernames exist within the system. The vulnerability specifically affects the account validation logic that fails to implement proper anti-automation measures such as CAPTCHA challenges or request rate limiting. According to CWE-384, this represents a session management vulnerability where the system does not adequately protect against automated attacks.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks including credential stuffing, social engineering campaigns, and targeted phishing attempts. Attackers can leverage the discovered valid usernames to conduct password spraying attacks against multiple accounts or to craft more convincing phishing emails that appear to target legitimate users. The ability to discover real user names provides attackers with additional information for social engineering operations, making their attacks more convincing and effective. This vulnerability directly impacts the principle of least privilege and authentication security by allowing unauthorized parties to gain knowledge about legitimate user accounts without proper authorization.
The attack vector requires minimal technical expertise and can be executed through automated tools that systematically test various username combinations against the vulnerable endpoints. The vulnerability is particularly concerning because it affects multiple Cisco Webex platforms, amplifying the potential impact across different collaboration scenarios. Organizations using these platforms face increased risk of account compromise and data breaches when this vulnerability remains unpatched. The lack of CAPTCHA protection represents a failure in the defense-in-depth strategy and violates fundamental security principles for web application authentication mechanisms. Security professionals should consider this vulnerability in the context of ATT&CK technique T1078 which covers valid accounts and credential access methods.
Mitigation strategies should include immediate implementation of CAPTCHA protection on all authentication-related endpoints, along with the deployment of rate limiting and request throttling mechanisms to prevent automated enumeration attempts. Organizations should also implement account lockout policies after failed authentication attempts and consider multi-factor authentication for critical accounts. The patching process should be prioritized at the highest level, as this vulnerability provides attackers with the initial reconnaissance necessary for more advanced attacks. Network monitoring should be enhanced to detect unusual patterns of authentication requests that may indicate account enumeration attempts, while security teams should review access controls and authentication mechanisms across all Cisco Webex platforms to ensure comprehensive protection against similar vulnerabilities.