CVE-2018-15430 in Expressway
Summary
by MITRE
A vulnerability in the administrative web interface of Cisco Expressway Series and Cisco TelePresence Video Communication Server (VCS) could allow an authenticated, remote attacker to execute code with user-level privileges on the underlying operating system. The vulnerability is due to insufficient validation of the content of upgrade packages. An attacker could exploit this vulnerability by uploading a malicious archive to the Upgrade page of the administrative web interface. A successful exploit could allow the attacker to execute code with user-level privileges on the underlying operating system.
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Analysis
by VulDB Data Team • 05/22/2023
The vulnerability identified as CVE-2018-15430 represents a critical security flaw within Cisco's Expressway Series and TelePresence Video Communication Server products, specifically targeting their administrative web interface. This weakness stems from inadequate input validation mechanisms that fail to properly scrutinize the contents of upgrade packages submitted through the system's upgrade functionality. The vulnerability affects multiple Cisco VCS platforms including the Cisco VCS-C, VCS-E, and Expressway-C and Expressway-E series devices, creating a significant risk for organizations relying on these communication infrastructure components for their video conferencing and unified communications services.
The technical exploitation of this vulnerability occurs through a straightforward yet dangerous attack vector involving the upload of malicious archive files to the upgrade page of the administrative web interface. When an authenticated attacker successfully uploads a crafted package, the system's insufficient validation allows the malicious content to be processed and executed within the operating system environment. This flaw falls under the CWE-774 category of inadequate input validation, where the system fails to properly examine or sanitize the data being submitted for processing. The vulnerability specifically targets the upgrade mechanism, which is a legitimate administrative function that should only accept verified, legitimate software packages.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with user-level access to the underlying operating system of the affected devices. This access level allows adversaries to potentially modify system configurations, install additional malicious software, access sensitive communication data, or establish persistence mechanisms within the network infrastructure. The remote nature of the attack means that an authenticated attacker could exploit this vulnerability from outside the organization's network perimeter, making it particularly dangerous for organizations with exposed administrative interfaces. From an attack chain perspective, this vulnerability aligns with ATT&CK technique T1078 for Valid Accounts and T1059 for Command and Scripting Interpreter, as it leverages legitimate administrative access to execute unauthorized commands.
Organizations affected by this vulnerability should immediately implement mitigation strategies including restricting access to the administrative web interface through network segmentation, implementing strict access controls and authentication mechanisms, and monitoring for unauthorized upgrade package uploads. The Cisco Security Advisory recommends disabling the upgrade functionality when not actively being used, applying the latest firmware patches, and implementing network access controls to limit administrative interface exposure. Additionally, organizations should conduct regular security assessments of their communication infrastructure to identify similar validation weaknesses and establish robust monitoring procedures for detecting anomalous upgrade activities. The vulnerability highlights the critical importance of input validation in web applications and demonstrates how seemingly benign administrative functions can become attack vectors when proper security controls are not implemented.