CVE-2017-12130 in tinysvcmdns Library
Summary
by MITRE
An exploitable NULL pointer dereference vulnerability exists in the tinysvcmdns library version 2017-11-05. A specially crafted packet can make the library dereference a NULL pointer leading to a server crash and denial of service. An attacker needs to send a DNS query to trigger this vulnerability.
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Analysis
by VulDB Data Team • 02/02/2023
The CVE-2017-12130 vulnerability represents a critical NULL pointer dereference flaw within the tinysvcmdns library, a lightweight DNS service discovery implementation commonly used in embedded systems and network applications. This vulnerability stems from inadequate input validation within the DNS packet processing logic, where the library fails to properly handle malformed or specially crafted DNS queries. The tinysvcmdns library serves as a minimal DNS implementation for service discovery in local networks, making it a common component in IoT devices, network appliances, and embedded systems where lightweight DNS functionality is required. The vulnerability specifically manifests when the library encounters a particular DNS query structure that causes internal pointer variables to remain uninitialized or set to NULL, leading to immediate system termination upon attempted dereference.
The technical exploitation of this vulnerability follows a predictable pattern where an attacker crafts a malicious DNS packet that triggers the NULL pointer dereference condition within the library's processing functions. When the library receives this malformed query, it attempts to access a pointer that has not been properly initialized, resulting in a segmentation fault or access violation that crashes the hosting application. This behavior directly maps to CWE-476, which describes NULL pointer dereference vulnerabilities where a null pointer is accessed without proper validation. The vulnerability's impact is particularly severe in networked environments where the affected service discovery functionality is exposed to untrusted network traffic, as it allows for remote denial of service attacks that can disrupt legitimate network operations and service availability.
The operational impact of CVE-2017-12130 extends beyond simple service disruption, as it can affect the stability of entire network infrastructures that depend on the affected library. In embedded systems and IoT devices, where the tinysvcmdns library is frequently integrated for service discovery, a successful exploitation can render devices inoperable until manual intervention or system reboot occurs. The vulnerability's accessibility makes it particularly dangerous as it requires minimal technical expertise to exploit, with the attacker only needing to send a specially crafted DNS query to the target system. This characteristic aligns with ATT&CK technique T1499.004, which describes network denial of service attacks that target network infrastructure components. The vulnerability's presence in widely deployed network discovery services means that organizations may experience cascading failures when multiple devices or services within their network infrastructure are simultaneously affected.
Mitigation strategies for CVE-2017-12130 should prioritize immediate patching of the affected tinysvcmdns library to version 2017-11-27 or later, which contains the necessary fixes for the NULL pointer dereference condition. Network administrators should implement input validation and filtering mechanisms at network boundaries to prevent malformed DNS queries from reaching vulnerable systems. Additionally, monitoring systems should be configured to detect unusual DNS traffic patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of proper pointer validation and input sanitization in network service implementations, particularly in embedded systems where resource constraints may limit the ability to implement comprehensive security measures. Organizations should also consider implementing network segmentation to isolate systems running vulnerable versions of the library, reducing the potential impact of successful exploitation attempts. The fix typically involves adding proper NULL checks before pointer dereference operations and ensuring that all input validation occurs before processing DNS packets.