CVE-2007-4553 in ST 2030 SIP phone
Summary
by MITRE
The Thomson ST 2030 SIP phone with software 1.52.1 allows remote attackers to cause a denial of service (device hang) via an INVITE message with a Via header that contains a / (slash) instead of the required space following the SIP version number.
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Analysis
by VulDB Data Team • 11/28/2024
The vulnerability identified as CVE-2007-4553 affects the Thomson ST 2030 SIP phone running software version 1.52.1, representing a critical denial of service weakness that can be exploited remotely by malicious actors. This issue stems from improper validation of SIP protocol messages within the device's signaling stack, specifically targeting the processing of INVITE requests that contain malformed Via headers. The vulnerability is categorized under CWE-129, which addresses improper validation of input data, and falls within the broader category of protocol processing flaws that can lead to system instability. The device's failure to properly parse the SIP version field in the Via header demonstrates a fundamental weakness in input sanitization and protocol compliance validation.
The technical flaw manifests when the SIP phone receives an INVITE message containing a Via header with a slash character instead of the required space separator between the SIP version and the transport protocol identifier. This malformed header construction violates the SIP specification defined in RFC 3261, which mandates proper formatting of the Via header field to ensure reliable communication between SIP entities. The device's parser fails to handle this specific malformed input gracefully, causing the system to enter an undefined state that results in a complete device hang or crash. This behavior represents a classic example of a buffer overflow or parsing error that can be triggered through crafted network traffic without requiring authentication or privileged access.
The operational impact of this vulnerability extends beyond simple service disruption, as it can effectively render the entire communication system unusable for legitimate users within the affected network. Attackers can exploit this weakness to perform persistent denial of service attacks against business-critical telephony infrastructure, potentially causing significant operational downtime and financial losses. The vulnerability's remote exploitation capability means that attackers can target devices from outside the local network perimeter, making it particularly dangerous for organizations that deploy these phones in distributed environments or connect them to public networks. This weakness directly aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates how protocol-level vulnerabilities can be weaponized to compromise availability.
Mitigation strategies for this vulnerability should include immediate firmware updates from Thomson to address the parsing logic error and implement proper input validation for SIP headers. Network administrators should consider implementing SIP protocol filtering rules at network boundaries to prevent malformed INVITE messages from reaching vulnerable devices. Additionally, deploying intrusion detection systems capable of identifying suspicious SIP traffic patterns can provide early warning of exploitation attempts. The device should be configured with strict SIP message validation policies and network segmentation to limit the potential impact of successful attacks. Organizations should also establish incident response procedures specifically addressing SIP protocol vulnerabilities and maintain detailed logs of SIP traffic for forensic analysis purposes. This vulnerability highlights the critical importance of robust protocol validation in telephony systems and underscores the need for regular security assessments of network infrastructure components.