CVE-2017-6678 in VPC-DI
Summary
by MITRE
A vulnerability in the ingress UDP packet processing functionality of Cisco Virtualized Packet Core-Distributed Instance (VPC-DI) Software 19.2 through 21.0 could allow an unauthenticated, remote attacker to cause both control function (CF) instances on an affected system to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient handling of user-supplied data by the affected software. An attacker could exploit this vulnerability by sending crafted UDP packets to the distributed instance (DI) network addresses of both CF instances on an affected system. A successful exploit could allow the attacker to cause an unhandled error condition on the affected system, which would cause the CF instances to reload and consequently cause the entire VPC to reload, resulting in the disconnection of all subscribers and a DoS condition on the affected system. This vulnerability can be exploited via IPv4 traffic only. Cisco Bug IDs: CSCvc01665 CSCvc35565.
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Analysis
by VulDB Data Team • 12/29/2020
The vulnerability identified as CVE-2017-6678 resides within the Cisco Virtualized Packet Core-Distributed Instance (VPC-DI) software ecosystem, specifically targeting versions 19.2 through 21.0. This flaw represents a critical weakness in the ingress UDP packet processing mechanism that fundamentally undermines the stability and availability of the affected network infrastructure. The vulnerability operates at the core of the control function instances, which serve as essential components for maintaining network operations and subscriber connectivity within the VPC framework. The flaw manifests when the system fails to properly validate and handle user-supplied data during UDP packet processing, creating a pathway for malicious actors to disrupt service continuity.
The technical exploitation of this vulnerability requires an attacker to craft and transmit specially designed UDP packets to the distributed instance network addresses of both control function instances within the affected system. This attack vector operates exclusively over IPv4 traffic, limiting its scope while maintaining significant impact potential. The insufficient data handling mechanism within the VPC-DI software creates an unhandled error condition when processing these crafted packets, leading to immediate system reload operations. The cascading effect of this vulnerability is particularly severe as it triggers reloads of both CF instances simultaneously, which subsequently causes the entire VPC system to restart. This comprehensive reload process results in complete disconnection of all subscribers and establishes a denial of service condition that can persist until manual intervention restores normal operations.
From a cybersecurity perspective, this vulnerability aligns with CWE-129, which addresses issues related to insufficient input validation, and demonstrates characteristics consistent with ATT&CK technique T1498, specifically covering network denial of service attacks. The vulnerability's remote exploitation capability without authentication requirements makes it particularly dangerous as it can be leveraged by attackers from any location with network access to the targeted system. The impact extends beyond simple service disruption to encompass complete system reinitialization, potentially causing data loss, session termination, and extended periods of network unavailability that can severely impact enterprise operations and service level agreements. The vulnerability affects the fundamental operational integrity of the VPC-DI platform, making it a critical concern for network operators who rely on these systems for core telecommunications infrastructure.
Organizations affected by this vulnerability should implement immediate mitigations including network segmentation to restrict access to the affected VPC-DI instances, deployment of network access control lists to filter UDP traffic, and application of the vendor-provided security patches referenced in the Cisco bug IDs CSCvc01665 and CSCvc35565. The remediation process should prioritize the immediate patching of all affected systems while maintaining comprehensive monitoring to detect potential exploitation attempts. Additionally, network administrators should consider implementing intrusion detection systems specifically configured to identify and alert on suspicious UDP packet patterns that could indicate attempted exploitation of this vulnerability. The implementation of these defensive measures should be complemented by regular security assessments to ensure that similar vulnerabilities are not present in other network components that may be susceptible to analogous attack vectors.