CVE-2007-3349 in 9112i SIP Phone
Summary
by MITRE
The Aastra 9112i SIP Phone with firmware 1.4.0.1048 and boot version 1.1.0.10 allows remote attackers to (1) cause a denial of service (device freeze) via a malformed SIP message of a certain length or (2) cause a denial of service (continuous ring) via a malformed SIP message of a certain other length.
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Analysis
by VulDB Data Team • 10/25/2017
The Aastra 9112i SIP Phone represents a significant vulnerability in enterprise communication infrastructure through CVE-2007-3349, which exposes critical flaws in SIP message processing mechanisms. This vulnerability affects firmware version 1.4.0.1048 and boot version 1.1.0.10, indicating a widespread issue within the device's signaling protocol implementation that lacks proper input validation and error handling. The vulnerability manifests through two distinct denial of service conditions that demonstrate fundamental weaknesses in the phone's SIP stack processing capabilities, making it susceptible to remote exploitation without requiring authentication or privileged access.
The technical flaw stems from inadequate validation of SIP message structures within the phone's communication stack, specifically when processing malformed SIP messages of predetermined lengths. The first variant causes a device freeze through a carefully crafted SIP message that, when processed by the phone's SIP parser, triggers an unexpected state transition or memory corruption that results in complete system freeze. This represents a classic buffer overflow or parsing error condition that falls under CWE-129, which describes improper validation of length parameters. The second variant creates a continuous ring condition by exploiting different message length parameters that cause the phone's ring tone generator to enter an infinite loop or malfunction, demonstrating how seemingly innocuous input validation failures can create persistent service disruption scenarios.
The operational impact of this vulnerability extends beyond simple service interruption to create potential business continuity risks for organizations relying on these communication devices. The device freeze condition can render critical communication endpoints unavailable for extended periods, potentially disrupting emergency services, customer support operations, or internal business communications. The continuous ring condition creates additional operational challenges by generating persistent audio alerts that can overwhelm users and potentially interfere with other communication systems. Both conditions can be triggered remotely, meaning attackers can exploit these vulnerabilities from outside the network perimeter, making them particularly dangerous in enterprise environments where physical access to devices is restricted.
Organizations should implement immediate mitigations including network segmentation to isolate these devices from untrusted networks, deployment of SIP message filtering appliances, and implementation of intrusion detection systems monitoring for abnormal SIP traffic patterns. The vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, and represents a clear example of how insufficient input validation in networked devices can create exploitable conditions. Regular firmware updates and vulnerability assessments should be conducted to ensure device security posture remains intact, while network administrators should monitor for suspicious SIP traffic patterns that may indicate exploitation attempts. The vulnerability demonstrates the critical importance of robust input validation in telecommunications equipment and highlights the need for comprehensive security testing of communication protocols before deployment in production environments.