CVE-2017-12310 in Spark Hybrid Calendar Service
Summary
by MITRE
A vulnerability in the auto discovery phase of Cisco Spark Hybrid Calendar Service could allow an unauthenticated, remote attacker to view sensitive information in the unencrypted headers of an HTTP method request. The attacker could use this information to conduct additional reconnaissance attacks leading to the disclosure of sensitive customer data. The vulnerability exists in the auto discovery phase because an unencrypted HTTP request is made due to requirements for implementing the Hybrid Calendar service. An attacker could exploit this vulnerability by monitoring the unencrypted traffic on the network. An exploit could allow the attacker to access sensitive customer data belonging to Office365 users, such as email and calendar events. Cisco Bug IDs: CSCvg35593.
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Analysis
by VulDB Data Team • 01/17/2020
The vulnerability identified as CVE-2017-12310 resides within Cisco Spark Hybrid Calendar Service's auto discovery phase, representing a critical security flaw that exposes sensitive data through unencrypted HTTP communications. This weakness fundamentally undermines the security posture of organizations relying on Cisco's collaboration platform, particularly those utilizing hybrid calendar services that bridge on-premises and cloud environments. The vulnerability manifests during the initial service discovery process where the system makes unencrypted HTTP requests to establish connectivity, creating an attack surface that malicious actors can exploit without authentication. The underlying technical implementation requires this unencrypted communication for proper service integration, but this design choice introduces significant risk to customer data confidentiality.
The operational impact of this vulnerability extends beyond simple information disclosure, creating opportunities for sophisticated reconnaissance attacks that can lead to comprehensive data breaches. Attackers monitoring network traffic can intercept and analyze the unencrypted HTTP headers to gather sensitive information about Office365 user accounts, including email addresses, calendar event details, and potentially other metadata that could be leveraged for further attacks. This vulnerability directly aligns with CWE-319 - Cleartext Transmission of Sensitive Information, which specifically addresses the exposure of confidential data through unencrypted network communications. The attack vector is particularly dangerous because it requires no authentication credentials, making it accessible to any network observer with basic packet capture capabilities.
From a threat modeling perspective, this vulnerability enables adversaries to conduct targeted reconnaissance attacks that can escalate into more severe compromises. The information gathered through monitoring unencrypted headers could reveal user activity patterns, organizational structures, and sensitive calendar data that might contain confidential business information or personal details. This exposure represents a significant risk to enterprise security, as calendar data often contains sensitive meeting information, project details, and personal communications that could be exploited for social engineering attacks or targeted breaches. The vulnerability also aligns with ATT&CK technique T1046 - Network Service Scanning, as it allows attackers to discover and map service endpoints through the analysis of unencrypted traffic patterns and header information.
Organizations affected by this vulnerability should implement immediate mitigations including network segmentation to isolate critical services, deployment of network monitoring tools to detect and alert on suspicious traffic patterns, and consideration of alternative service configurations that eliminate the need for unencrypted communications during discovery phases. The recommended approach involves upgrading to patched versions of Cisco Spark Hybrid Calendar Service that implement encrypted communication protocols for service discovery, ensuring that all headers and payload data are protected through TLS encryption. Security teams should also conduct thorough network audits to identify and remediate any other instances of cleartext communication within their hybrid environments, as this vulnerability demonstrates the broader risk of unencrypted service discovery processes in enterprise collaboration platforms.