CVE-2022-47516 in drachtio-server
Summary
by MITRE • 12/18/2022
An issue was discovered in the libsofia-sip fork in drachtio-server before 0.8.20. It allows remote attackers to cause a denial of service (daemon crash) via a crafted UDP message that leads to a failure of the libsofia-sip-ua/tport/tport.c self assertion.
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Analysis
by VulDB Data Team • 04/18/2025
The vulnerability identified as CVE-2022-47516 resides within the libsofia-sip component of the drachtio-server software ecosystem, specifically affecting versions prior to 0.8.20. This issue represents a critical denial of service vulnerability that can be exploited by remote attackers to crash the daemon process, effectively rendering the service unavailable to legitimate users. The vulnerability manifests through a carefully crafted UDP message that triggers an assertion failure within the transport layer implementation of the SIP stack.
The technical flaw occurs within the libsofia-sip-ua/tport/tport.c module where a self assertion fails when processing malformed UDP packets. This assertion failure represents a fundamental breakdown in the software's error handling mechanisms, where the system does not properly validate incoming UDP message structures before attempting to process them. The assertion failure causes the daemon to terminate abruptly, leading to a complete service disruption that requires manual intervention to restore normal operations. This type of vulnerability falls under the CWE-611 weakness category, specifically related to improper restriction of operations within a recognized security scope, where the system fails to properly validate input data before processing.
The operational impact of this vulnerability extends beyond simple service disruption as it can be exploited by attackers to launch coordinated denial of service attacks against drachtio-server instances. Since the vulnerability is remote in nature, attackers do not require physical access to the system to exploit it, making it particularly dangerous in networked environments where SIP services are exposed to external traffic. The daemon crash results in immediate service unavailability, potentially affecting VoIP communications, session initiation protocols, and any other services dependent on the drachtio-server infrastructure. This vulnerability directly maps to the ATT&CK technique T1499.004 which involves network denial of service attacks that target specific services or protocols.
Mitigation strategies for CVE-2022-47516 should prioritize immediate patching of affected drachtio-server installations to version 0.8.20 or later where the vulnerability has been addressed through proper input validation and assertion handling. Network administrators should implement UDP filtering rules at the firewall level to restrict incoming SIP traffic to known legitimate sources, while also deploying intrusion detection systems that can identify and alert on malformed UDP packets targeting SIP ports. Additionally, implementing redundant service architectures with automatic failover mechanisms can help minimize the impact of such attacks by ensuring that service disruption does not result in complete system outages. The vulnerability highlights the importance of robust input validation and proper error handling in security-critical network applications, particularly those implementing real-time communication protocols that are frequently targeted by malicious actors seeking to disrupt services.