CVE-2007-1693 in Yet Another Telephony Engine
Summary
by MITRE
The SIP channel module in Yet Another Telephony Engine (Yate) before 1.2.0 sets the caller_info_uri parameter using a incorrect variable that can be NULL, which allows remote attackers to cause a denial of service (NULL dereference and application crash) via a Call-Info header without a purpose parameter.
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Analysis
by VulDB Data Team • 10/17/2017
The vulnerability identified as CVE-2007-1693 affects the SIP channel module within Yet Another Telephony Engine Yate version 1.2.0 and earlier. This represents a critical security flaw that demonstrates poor input validation and memory management practices within telephony software systems. The issue stems from how the system handles Call-Info headers during SIP session establishment, creating a scenario where remote attackers can manipulate the application's behavior through crafted SIP messages.
The technical root cause of this vulnerability lies in the improper handling of the caller_info_uri parameter within the SIP channel module. Specifically, the software utilizes a variable that can potentially be NULL when processing the Call-Info header, which lacks a purpose parameter. This NULL value assignment creates a condition where subsequent operations attempt to dereference a null pointer, leading to application instability. The flaw manifests as a NULL dereference error that ultimately results in a complete application crash, effectively causing a denial of service condition that disrupts legitimate telephony services.
From an operational perspective, this vulnerability presents significant risks to telephony infrastructure and communication services. Attackers can exploit this weakness remotely without requiring authentication or privileged access, making it particularly dangerous in production environments. The denial of service impact means that legitimate users cannot establish or maintain SIP sessions through affected Yate installations, potentially disrupting business communications, emergency services, or other critical telephony functions. This vulnerability directly aligns with CWE-476, which describes NULL pointer dereference conditions that can lead to application crashes and system instability.
The attack surface for this vulnerability extends across any system utilizing Yate versions prior to 1.2.0 that process SIP traffic, particularly those handling incoming calls or managing SIP channel connections. Network-based exploitation is straightforward since attackers only need to send specially crafted SIP messages containing malformed Call-Info headers to trigger the NULL dereference condition. This makes the vulnerability particularly attractive to threat actors seeking to disrupt telephony services without requiring complex attack chains or specialized tools.
Mitigation strategies for this vulnerability primarily involve upgrading to Yate version 1.2.0 or later, where the NULL pointer dereference issue has been addressed through proper input validation and variable initialization. System administrators should also implement network-level controls to monitor and filter SIP traffic for malformed headers, though this approach provides only partial protection. Additionally, organizations should consider implementing intrusion detection systems that can identify suspicious SIP message patterns and establish proper logging mechanisms to detect exploitation attempts. The vulnerability demonstrates the importance of proper memory management and input validation practices in telephony software, aligning with ATT&CK technique T1499.1 for network denial of service attacks and highlighting the need for robust software security practices in communication infrastructure.