CVE-2007-3441 in 9112i SIP Phone
Summary
by MITRE
Format string vulnerability in the Aastra 9112i SIP Phone with firmware 1.4.0.1048 and boot version 1.1.0.10 allows remote attackers to cause a denial of service (blocked call reception and slow calling) via format string specifiers in an SDP header value, a different vulnerability than CVE-2007-3349.
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Analysis
by VulDB Data Team • 10/26/2017
The vulnerability identified as CVE-2007-3441 represents a critical format string flaw in the Aastra 9112i SIP phone firmware version 1.4.0.1048 and boot version 1.1.0.10. This issue falls under the broader category of software security weaknesses that can lead to significant operational disruptions in voice communication systems. The vulnerability specifically manifests when the device processes Session Description Protocol headers containing malicious format string specifiers, creating a pathway for remote exploitation that impacts core telephony functions.
The technical flaw stems from improper input validation within the SIP phone's handling of SDP header values, where the device fails to properly sanitize or escape user-supplied data before processing it through format string functions. This weakness allows attackers to inject malicious format specifiers that can manipulate how the device interprets and processes incoming call data. The vulnerability is classified as a CWE-134 weakness, which specifically addresses the use of user-supplied format strings without proper validation or sanitization, making it susceptible to exploitation through crafted malicious SIP packets.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it creates a persistent degradation of service quality that affects both incoming call reception and overall calling performance. When exploited, the format string vulnerability causes the phone to become unresponsive to incoming calls while simultaneously slowing down the processing of outgoing calls, effectively rendering the device unusable for its primary function. This degradation occurs because the malicious format specifiers interfere with the phone's internal memory management and processing routines, causing system instability and resource exhaustion. The vulnerability is distinct from CVE-2007-3349, indicating that multiple weaknesses exist within the same device firmware, each requiring specific mitigation approaches.
Organizations utilizing Aastra 9112i SIP phones must implement immediate mitigation strategies to protect their communication infrastructure from exploitation attempts. The most effective approach involves firmware updates from the vendor, which typically include proper input validation mechanisms and sanitization routines for SDP header processing. Network-level protections such as SIP filtering and packet inspection can provide additional defense-in-depth measures, particularly in environments where immediate firmware updates are not immediately feasible. Security monitoring should focus on detecting unusual SIP traffic patterns and malformed SDP headers that could indicate attempted exploitation. The vulnerability demonstrates the critical importance of validating all user-supplied input in telephony systems and aligns with ATT&CK technique T1210 which addresses exploitation of software vulnerabilities in network infrastructure devices. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of such vulnerabilities within their broader communication networks.