Summary
Netcore NAP930 contains an OS command injection vulnerability in the Network Tools CGI, where the sid argument reaches an unsafe eval operation. A remote attacker may exploit this behavior to execute commands on the device when the affected CGI endpoint is reachable and accepts attacker-controlled input.
Affected context
The vulnerability occurs in the /www/cgi-bin/network_tools component of Netcore NAP930 0.1.241010.141410. It becomes risky when the Network Tools CGI is exposed to a network reachable by an attacker and the sid parameter is processed through dynamic evaluation without sufficient command separation, validation, or contextual escaping.
Exploit preconditions
- Attack surface: Network-accessible Network Tools CGI endpoint
- Required access: Ability to send requests to the affected endpoint; authentication requirements are not established by the available description
- Trigger point: Processing of the
sidargument by the CGI'sevalfunction - Why exploitation is possible: Attacker-controlled input reaches command or code evaluation without adequate restrictions, allowing shell-level operations to be interpreted by the device
Why this happens
The underlying bug is an unsafe use of dynamic evaluation with externally influenced input. Rather than treating sid as constrained data, the application permits its contents to participate in command execution, creating a direct path from request parameters to operating-system commands. This behavior maps primarily to CWE-78: Improper Neutralization of Special Elements used in an OS Command, with CWE-77: Improper Neutralization of Special Elements in Command also describing the broader command-injection class.
Potential impact
- An attacker may execute arbitrary operating-system commands on the device
- Device configuration, credentials, or operational data could be exposed
- Network traffic may be monitored, altered, or redirected
- The device could be used for further compromise of connected systems
- Availability may be reduced through service disruption or destructive commands
General mitigation guidance
Mitigation generally focuses on removing dynamic evaluation from request-processing paths and reducing the trust placed in CGI parameters.
Common defensive patterns include:
- Replacing
evaland shell command construction with fixed, allowlisted operations - Treating
sidas a strictly typed identifier with length, format, and range validation - Using structured process APIs that pass arguments separately rather than invoking a shell
- Applying context-appropriate escaping only as a secondary defense, not as the primary control
- Restricting administrative CGI exposure through network segmentation and access policies
- Running services with the minimum filesystem, process, and network privileges required
- Logging rejected input and administrative actions without recording sensitive values
How teams detect issues like this
Organizations can look for this vulnerability class through:
- Static analysis rules identifying
eval, shell invocation, and command-building functions that consume CGI or request parameters - Code review signals such as string concatenation involving query arguments and operating-system command APIs
- Dynamic testing that supplies unexpected metacharacters and verifies that input remains data rather than executable syntax
- Web application firewall or gateway policies limiting access to administrative CGI endpoints
- Runtime monitoring for unusual child processes, command interpreters, outbound connections, or changes initiated by the web-service account
- Automated security review tools that flag data flows from HTTP parameters to dynamic evaluation or process execution
