CVE-2024-45518 is a vulnerability in Zimbra Collaboration Suite (ZCS) versions 8.8.15 (before Patch 46), 9.0.0 (before Patch 41), 10.0.x (before 10.0.9), and 10.1.x (before 10.1.1). It arises from improper input sanitization combined with misconfigured domain whitelisting, which allows authenticated users to exploit Server-Side Request Forgery (SSRF). SSRF vulnerabilities enable attackers to make HTTP requests from the vulnerable server to internal or external systems that are otherwise inaccessible. In this case, the SSRF can be chained with command injection vulnerabilities present in internal services, leading to Remote Code Execution (RCE). This means an attacker can execute arbitrary commands on the server hosting Zimbra, potentially gaining full control. Furthermore, if existing Cross-Site Scripting (XSS) vulnerabilities are present, they can be leveraged alongside the SSRF to escalate the attack impact. The vulnerability requires authentication but no additional user interaction, and the attack complexity is moderate due to the need to chain multiple flaws. The CVSS v3.1 score of 7.5 reflects high confidentiality, integrity, and availability impacts. The vulnerability is classified under CWE-918 (Server-Side Request Forgery). No public exploit code or active exploitation has been reported yet. The issue emphasizes the risks of improper input validation and domain whitelisting misconfigurations in web applications that interact with internal services.

The impact of CVE-2024-45518 is significant for organizations using affected Zimbra Collaboration Suite versions. Successful exploitation can lead to Remote Code Execution on the mail server, compromising the confidentiality, integrity, and availability of email communications and potentially the entire server environment. Attackers could pivot from the mail server to internal networks, accessing sensitive data or disrupting services. The ability to send unauthorized HTTP requests internally can expose internal APIs and services that are not hardened against external threats. Combining SSRF with command injection and XSS vulnerabilities increases the attack surface and potential damage. This could result in data breaches, service outages, and loss of trust. Given Zimbra's widespread use in enterprises, educational institutions, and government agencies, the threat is broad and could affect critical communications infrastructure globally.

1. Immediately apply the latest patches provided by Zimbra for versions 8.8.15, 9.0.0, 10.0.x, and 10.1.x to remediate the vulnerability. 2. Review and tighten domain whitelisting configurations to ensure only trusted domains are allowed for internal requests. 3. Implement strict input validation and sanitization on all user-supplied data that can influence server-side requests. 4. Conduct a thorough security assessment of internal services accessible via the mail server to identify and remediate command injection or other vulnerabilities. 5. Monitor logs for unusual internal HTTP requests originating from the mail server that could indicate SSRF attempts. 6. Harden the Zimbra server environment by applying least privilege principles and network segmentation to limit the impact of potential RCE. 7. Regularly scan for and remediate XSS vulnerabilities to reduce the risk of chained attacks. 8. Educate administrators on secure configuration best practices for Zimbra and internal services. 9. Consider deploying Web Application Firewalls (WAFs) with rules to detect and block SSRF patterns targeting internal resources.