CVE-2018-16666 in Contiki-NG
Summary
by MITRE
An issue was discovered in Contiki-NG through 4.1. There is a stack-based buffer overflow in next_string in os/storage/antelope/aql-lexer.c while parsing AQL (parsing next string).
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Analysis
by VulDB Data Team • 05/07/2023
The vulnerability identified as CVE-2018-16666 represents a critical stack-based buffer overflow flaw within the Contiki-NG operating system version 4.1 and earlier. This issue resides in the AQL (Antelope Query Language) lexer component, specifically within the next_string function located in os/storage/antelope/aql-lexer.c. The flaw manifests during the parsing of AQL strings, making it particularly dangerous in environments where malformed input data might be processed. The vulnerability is classified under CWE-121 Stack-based Buffer Overflow, which occurs when data is written beyond the bounds of a fixed-length buffer allocated on the stack, potentially leading to arbitrary code execution or system instability.
The technical exploitation of this vulnerability requires an attacker to craft malicious AQL input that triggers the buffer overflow condition within the next_string function. When the lexer processes malformed string data, it fails to properly validate input lengths against the allocated buffer size, allowing attackers to overwrite adjacent stack memory. This condition can be leveraged to execute arbitrary code with the privileges of the affected process, potentially leading to complete system compromise. The vulnerability's impact is amplified in IoT and embedded systems where Contiki-NG is commonly deployed, as these environments often lack traditional security mitigations like stack canaries or address space layout randomization.
The operational implications of this vulnerability extend beyond simple exploitation scenarios, as it affects the core storage and query processing capabilities of Contiki-NG systems. Networked embedded devices that utilize AQL for data manipulation or configuration may become vulnerable to remote code execution attacks, particularly in scenarios where external data sources are processed without proper sanitization. This vulnerability aligns with ATT&CK technique T1059.007 Command and Scripting Interpreter: PowerShell, as attackers could potentially leverage this overflow to execute malicious payloads through command injection mechanisms. The flaw particularly affects systems implementing the Antelope database storage subsystem, making it a significant concern for IoT deployments, sensor networks, and embedded communication devices that rely on Contiki-NG's lightweight operating system framework.
Mitigation strategies for CVE-2018-16666 should prioritize immediate patching of Contiki-NG to version 4.2 or later, which contains the necessary fixes for the buffer overflow condition. Organizations should implement input validation mechanisms at multiple layers, including runtime checks for string length validation and proper bounds checking in the AQL lexer component. Network segmentation and access controls should be enforced to limit potential attack surfaces, particularly for devices that process external AQL input. Additionally, security monitoring should be enhanced to detect anomalous parsing behavior or memory access patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of secure coding practices in embedded systems, particularly regarding buffer management and input validation, as highlighted in the OWASP Top Ten 2017 category A05: Security Misconfiguration and the NIST Cybersecurity Framework's Protect function. System administrators should also consider implementing intrusion detection systems specifically tuned to detect exploitation attempts targeting stack-based buffer overflow vulnerabilities in embedded operating systems.