CVE-2005-2181 in 7960 Router
Summary
by MITRE
Cisco 7940/7960 Voice over IP (VoIP) phones do not properly check the Call-ID, branch, and tag values in a NOTIFY message to verify a subscription, which allows remote attackers to spoof messages such as the "Messages waiting" message.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 07/25/2017
The vulnerability identified as CVE-2005-2181 affects Cisco 7940 and 7960 VoIP phones, representing a critical security flaw in the Session Initiation Protocol (SIP) implementation that governs voice communication over IP networks. These devices operate within enterprise and organizational environments where secure communication channels are paramount, making them attractive targets for malicious actors seeking to compromise voice services. The vulnerability stems from insufficient validation mechanisms within the SIP NOTIFY message processing capabilities of these telephony devices.
The technical flaw resides in the improper validation of Call-ID, branch, and tag values within SIP NOTIFY messages that are used to maintain subscriptions and deliver status updates to VoIP clients. Specifically, the Cisco phones fail to rigorously verify these critical identifiers that should ensure message authenticity and prevent unauthorized modifications to subscription states. This validation failure creates a window of opportunity for attackers to inject malicious NOTIFY messages that appear legitimate to the phone's SIP stack. The vulnerability operates at the application layer of the network stack, specifically targeting the SIP protocol implementation that governs VoIP communications.
The operational impact of this vulnerability is significant as it allows remote attackers to spoof critical messaging services that are integral to VoIP functionality. Attackers can manipulate the "Messages waiting" indicator that appears on the phone displays, potentially leading to social engineering attacks where users might be misled about their voicemail status. Beyond simple message spoofing, this vulnerability could enable more sophisticated attacks including unauthorized access to voicemail systems, disruption of communication services, and potential escalation to full system compromise. The ability to manipulate subscription states means that attackers could potentially intercept legitimate communications or prevent users from receiving important notifications.
This vulnerability aligns with CWE-284, which addresses improper access control mechanisms in software systems, and represents a classic case of insufficient input validation that creates opportunities for message injection attacks. The attack vector is particularly concerning as it requires no local access or authentication credentials, making it a remote exploit that can be executed from anywhere on the network. From an ATT&CK framework perspective, this vulnerability maps to techniques involving spoofing and credential abuse, as attackers can effectively impersonate legitimate system messages and potentially gain unauthorized access to communication services. The lack of proper authentication verification in the SIP message processing creates a pathway for attackers to manipulate the phone's behavior without requiring direct system access or administrative privileges.
Organizations should implement immediate mitigations including network segmentation to isolate VoIP infrastructure, deployment of SIP-specific firewalls and intrusion detection systems, and regular firmware updates from Cisco to address the vulnerability. The implementation of secure SIP configurations that enforce strict message validation and authentication mechanisms is crucial. Additionally, network monitoring should be enhanced to detect anomalous SIP traffic patterns that might indicate exploitation attempts. Regular security assessments of VoIP systems should include testing for similar validation weaknesses in other telephony equipment and network infrastructure components.