CVE-2007-3438 in Sip Softphone
Summary
by MITRE
Buffer overflow in the SIP header parsing module in the Nortel PC Client SIP Soft Phone 4.1 3.5.208[20051015] allows remote attackers to execute arbitrary code via a malformed message, a different vulnerability than CVE-2007-3361.
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Analysis
by VulDB Data Team • 10/25/2017
The vulnerability described in CVE-2007-3438 represents a critical buffer overflow flaw within the Session Initiation Protocol header parsing functionality of Nortel PC Client SIP Soft Phone versions 4.1 and 3.5.208. This security weakness specifically affects the software's ability to process malformed SIP messages, creating an avenue for remote code execution attacks. The vulnerability is distinct from CVE-2007-3361, indicating separate attack vectors and exploitation mechanisms within the same software product. The affected version 3.5.208 was released in October 2005, making this a legacy vulnerability that persisted in older deployments of the Nortel communication software.
The technical implementation of this buffer overflow occurs during the parsing of SIP headers within the soft phone's communication stack. When the application receives a malformed SIP message containing overly long header values or crafted payload data, the parsing module fails to properly validate input boundaries before copying data into fixed-size buffers. This classic buffer overflow condition allows attackers to overwrite adjacent memory locations, potentially including return addresses, function pointers, or other critical control data. The vulnerability stems from inadequate bounds checking and memory management practices in the SIP processing code, which directly violates established secure coding principles.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on Nortel PC Client SIP Soft Phones for voice communication services. Remote attackers can exploit this weakness without requiring authentication or physical access to the target system, making it particularly dangerous in networked environments where SIP traffic flows freely. Successful exploitation could result in complete system compromise, allowing attackers to execute arbitrary code with the privileges of the affected application process. This capability enables various malicious activities including unauthorized access to communication channels, data exfiltration, or establishment of persistent backdoors within the network infrastructure.
The attack surface for this vulnerability extends beyond individual endpoints to encompass entire communication networks that utilize Nortel SIP soft phones. Network-based attackers can craft malicious SIP messages that trigger the buffer overflow when processed by vulnerable clients, potentially affecting multiple users simultaneously. The implications for enterprise environments are particularly severe as these devices often operate in trusted network zones, making them attractive targets for lateral movement attacks. Organizations implementing the affected software versions should consider the broader security implications of this vulnerability within their communication infrastructures.
Mitigation strategies for CVE-2007-3438 should prioritize immediate remediation through software updates and patches provided by Nortel or third-party vendors. Organizations must conduct comprehensive inventory assessments to identify all affected installations and implement network segmentation to limit exposure to potentially malicious SIP traffic. Firewall rules and SIP proxy configurations should be reviewed to restrict incoming SIP message processing from untrusted sources. Additionally, network monitoring solutions should be deployed to detect anomalous SIP traffic patterns that may indicate exploitation attempts. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a clear violation of ATT&CK technique T1059.007 for command and script injection through network protocols. Given the age of the affected software, long-term migration to supported communication platforms remains the most effective defense against this and similar legacy vulnerabilities.