CVE-2016-9956 in FlightGear
Summary
by MITRE
The route manager in FlightGear before 2016.4.4 allows remote attackers to write to arbitrary files via a crafted Nasal script.
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Analysis
by VulDB Data Team • 09/15/2024
The vulnerability identified as CVE-2016-9956 resides within the route manager component of FlightGear, an open-source flight simulator software that has been widely adopted for both recreational and educational purposes. This particular flaw affects versions prior to 2016.4.4 and represents a critical security issue that could potentially allow remote attackers to execute arbitrary file write operations on systems running vulnerable versions. The vulnerability specifically targets the Nasal scripting engine, which is a scripting language used within FlightGear for extending functionality and creating custom behaviors. This scripting capability, while powerful for legitimate users, becomes a vector for exploitation when proper input validation and sanitization mechanisms are absent.
The technical nature of this vulnerability stems from insufficient validation of user-supplied data within the route manager functionality. When a user loads a crafted Nasal script, the system fails to properly sanitize or validate the script content before executing it. This allows attackers to inject malicious code that can manipulate the file system by writing to arbitrary locations on the target system. The flaw operates at the application level and does not require authentication or local access, making it particularly dangerous as it can be exploited remotely through various attack vectors including web-based interfaces or network protocols that may be used to transmit the malicious Nasal script to the vulnerable FlightGear instance.
The operational impact of this vulnerability extends beyond simple file system manipulation, as it could enable attackers to overwrite critical system files, install persistent backdoors, or execute arbitrary code with the privileges of the FlightGear process. In environments where FlightGear is used for training or simulation purposes, this vulnerability could compromise the integrity of training data, potentially leading to false information being presented to users. The attack surface is particularly concerning given FlightGear's widespread use in educational institutions, aviation training programs, and research environments where system integrity is paramount. This vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal attacks, and represents a classic example of how script execution vulnerabilities can be leveraged for arbitrary file system access.
Mitigation strategies for this vulnerability should focus on immediate remediation through version updates to FlightGear 2016.4.4 or later, which includes proper input validation and sanitization mechanisms for Nasal scripts. System administrators should also implement network segmentation and access controls to limit exposure of FlightGear instances to untrusted networks. Additional protective measures include disabling unnecessary scripting capabilities, implementing application whitelisting policies, and monitoring for suspicious file system activities. Organizations using FlightGear in production environments should conduct comprehensive security assessments and consider implementing network intrusion detection systems to monitor for potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation in interpreted scripting environments and aligns with ATT&CK technique T1059.007 for script execution, highlighting how legitimate scripting capabilities can be abused when proper security controls are not implemented.