CVE-2007-2293 in Asterisk
Summary
by MITRE
Multiple stack-based buffer overflows in the process_sdp function in chan_sip.c of the SIP channel T.38 SDP parser in Asterisk before 1.4.3 allow remote attackers to execute arbitrary code via a long (1) T38FaxRateManagement or (2) T38FaxUdpEC SDP parameter in an SIP message, as demonstrated using SIP INVITE.
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Analysis
by VulDB Data Team • 01/20/2025
The vulnerability described in CVE-2007-2293 represents a critical stack-based buffer overflow in the Asterisk telephony system's SIP channel implementation. This flaw exists within the process_sdp function located in chan_sip.c, specifically affecting the T.38 SDP parser used for handling fax over SIP communications. The vulnerability impacts Asterisk versions prior to 1.4.3, making it a significant concern for organizations running older telephony infrastructure. The issue manifests when processing SIP INVITE messages containing specially crafted SDP parameters that exceed buffer limits during parsing operations.
The technical exploitation of this vulnerability occurs through manipulation of two specific SDP parameters: T38FaxRateManagement and T38FaxUdpEC. When remote attackers craft SIP messages containing excessively long values for these parameters, the process_sdp function fails to properly validate input lengths before copying data into fixed-size stack buffers. This classic buffer overflow condition allows attackers to overwrite adjacent memory locations including return addresses and control data, potentially enabling arbitrary code execution with the privileges of the Asterisk process. The vulnerability is particularly dangerous because it operates within the core SIP processing functionality, meaning any SIP traffic could potentially trigger the overflow condition.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a pathway to compromise entire telephony infrastructure. Organizations relying on Asterisk for voice and fax services face significant risk of unauthorized access, service disruption, and potential data breaches. The vulnerability affects the fundamental SIP channel processing capability, making it difficult to isolate or patch specific components without upgrading the entire Asterisk system. Attackers can leverage this flaw to gain persistent access to telephony systems, potentially using the compromised infrastructure for further attacks or to establish unauthorized communication channels within network environments.
Security mitigation strategies for CVE-2007-2293 primarily focus on immediate system upgrades to Asterisk version 1.4.3 or later, where the buffer overflow has been addressed through proper input validation and bounds checking. Organizations should also implement network-level protections such as SIP message filtering and rate limiting to reduce exposure windows. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which is classified under the broader category of injection flaws in the CWE taxonomy. From an ATT&CK framework perspective, this vulnerability maps to T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation, representing a critical entry point for attackers seeking to establish persistent access to telephony systems. Network segmentation and monitoring of SIP traffic can help detect exploitation attempts, while regular security assessments should verify that all telephony infrastructure components are properly patched and updated against known vulnerabilities.