CVE-2018-10951 in Zimbra Collaboration
Summary
by MITRE
mailboxd in Zimbra Collaboration Suite 8.8 before 8.8.8; 8.7 before 8.7.11.Patch3; and 8.6 before 8.6.0.Patch10 allows zimbraSSLPrivateKey read access via a GetServer, GetAllServers, or GetAllActiveServers call in the Admin SOAP API.
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Analysis
by VulDB Data Team • 08/15/2025
The vulnerability identified as CVE-2018-10951 represents a critical information disclosure flaw within the Zimbra Collaboration Suite authentication and administrative framework. This vulnerability affects multiple versions of the Zimbra platform including the 8.8 series before 8.8.8, the 8.7 series before 8.7.11.Patch3, and the 8.6 series before 8.6.0.Patch10. The issue stems from improper access control mechanisms within the mailboxd service that handles administrative SOAP API calls, specifically targeting the GetServer, GetAllServers, and GetAllActiveServers endpoints.
The technical flaw manifests through the exposure of sensitive cryptographic material during administrative API interactions. When legitimate administrative users or attackers exploit this vulnerability, they can retrieve the zimbraSSLPrivateKey through the targeted SOAP API calls, effectively compromising the SSL/TLS encryption infrastructure that protects Zimbra communications. This represents a direct violation of the principle of least privilege and demonstrates a failure in the access control implementation within the Zimbra administrative interface. The vulnerability falls under the CWE-284 access control weakness category, specifically addressing insufficient access control mechanisms that allow unauthorized information disclosure.
The operational impact of this vulnerability extends far beyond simple information disclosure, as the exposure of SSL private keys can lead to complete compromise of encrypted communications within the Zimbra environment. An attacker who successfully exploits this vulnerability gains the ability to decrypt intercepted communications, impersonate legitimate services, and potentially escalate privileges within the Zimbra infrastructure. This vulnerability aligns with ATT&CK technique T1552.001, which covers credentials in files, as it exposes cryptographic keys that serve as authentication credentials for secure communications. The compromise of SSL private keys can result in man-in-the-middle attacks, data interception, and the potential for lateral movement within the network infrastructure that relies on Zimbra for email services.
Organizations affected by this vulnerability should implement immediate mitigation strategies including applying the vendor-provided patches for all affected versions, implementing network segmentation to restrict access to administrative APIs, and monitoring for suspicious administrative API usage patterns. The recommended approach includes disabling unnecessary administrative API endpoints, implementing strict authentication controls for administrative access, and conducting thorough security audits of the Zimbra configuration. Additionally, organizations should consider implementing intrusion detection systems to monitor for exploitation attempts of this specific vulnerability pattern, as the attack surface is primarily through the SOAP API interface that can be accessed from external networks if not properly restricted.