Summary
A critical command injection flaw in the Linksys E1700 Static Route Handler allows attacker-controlled values to reach operating-system command processing. Because the affected handler is remotely accessible, an unauthenticated or otherwise authorized remote attacker may be able to execute commands on the router when crafted static-route parameters are accepted.
A critical command injection flaw in the Linksys E1700 Static Route Handler allows attacker-controlled values to reach operating-system command processing. Because the affected handler is remotely accessible, an unauthenticated or otherwise authorized remote attacker may be able to execute commands on the router when crafted static-route parameters are accepted.
Affected context
The vulnerability occurs in the /goform/addStaticRoute endpoint and its addStaticRoute function when processing static-route settings. Risk is present when externally supplied values for IP address, netmask, gateway, or metric are incorporated into operating-system command execution without effective validation, escaping, or safer API boundaries.
The vulnerability occurs in the /goform/addStaticRoute endpoint and its addStaticRoute function when processing static-route settings. Risk is present when externally supplied values for IP address, netmask, gateway, or metric are incorporated into operating-system command execution without effective validation, escaping, or safer API boundaries.
Exploit preconditions
- Attack surface: Network-accessible Static Route Handler endpoint
- Required access: Access sufficient to reach the endpoint; authentication requirements may depend on the device configuration
- Trigger point: Processing of
staticRoute_IP_setting,staticRoute_Netmask_setting,staticRoute_Gateway_setting, orstaticRoute_Metric_setting - Why exploitation is possible: Untrusted parameter values may be interpreted as operating-system command syntax rather than as strictly bounded route configuration data
- Attack surface: Network-accessible Static Route Handler endpoint
- Required access: Access sufficient to reach the endpoint; authentication requirements may depend on the device configuration
- Trigger point: Processing of
staticRoute_IP_setting,staticRoute_Netmask_setting,staticRoute_Gateway_setting, orstaticRoute_Metric_setting - Why exploitation is possible: Untrusted parameter values may be interpreted as operating-system command syntax rather than as strictly bounded route configuration data
Why this happens
The underlying bug is improper neutralization of special elements in externally supplied operating-system command input. The handler appears to pass route-related parameters into a command execution path without reliably separating data from shell syntax. This 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 describing the broader command-injection class.
The underlying bug is improper neutralization of special elements in externally supplied operating-system command input. The handler appears to pass route-related parameters into a command execution path without reliably separating data from shell syntax. This 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 describing the broader command-injection class.
Potential impact
- An attacker may execute arbitrary commands on the router
- Device configuration or routing behavior could be altered
- Network traffic may be redirected, disrupted, or monitored
- The router may be used for persistence or attacks against connected systems
- Sensitive device or network information could be exposed
- An attacker may execute arbitrary commands on the router
- Device configuration or routing behavior could be altered
- Network traffic may be redirected, disrupted, or monitored
- The router may be used for persistence or attacks against connected systems
- Sensitive device or network information could be exposed
General mitigation guidance
Mitigation generally focuses on removing shell interpretation from route-management operations and reducing trust in request parameters.
Common defensive patterns include:
- Use dedicated networking APIs or structured system interfaces instead of constructing shell commands
- Apply strict allowlists and type-aware validation for addresses, masks, gateways, and metrics
- Use fixed argument vectors with process APIs that do not invoke a shell when command execution is unavoidable
- Enforce authentication and authorization for administrative route-management functions
- Run management services with the minimum privileges required to update routing state
- Restrict network exposure of administrative endpoints and apply request filtering at trusted boundaries
Mitigation generally focuses on removing shell interpretation from route-management operations and reducing trust in request parameters.
Common defensive patterns include:
- Use dedicated networking APIs or structured system interfaces instead of constructing shell commands
- Apply strict allowlists and type-aware validation for addresses, masks, gateways, and metrics
- Use fixed argument vectors with process APIs that do not invoke a shell when command execution is unavoidable
- Enforce authentication and authorization for administrative route-management functions
- Run management services with the minimum privileges required to update routing state
- Restrict network exposure of administrative endpoints and apply request filtering at trusted boundaries
How teams detect issues like this
Detection approaches can include:
- Static analysis for shell invocation, command concatenation, and user-controlled values reaching process execution APIs
- Code review checks for route parameters used in formatted command strings
- Tests using malformed and boundary-value route inputs to verify strict rejection and correct type handling
- Web application firewall or gateway policies monitoring unexpected shell metacharacters in administrative parameters
- Runtime monitoring for unusual process creation, command execution, or route changes originating from the management service
- Automated security review tools that identify command-injection data flows during development
Detection approaches can include:
- Static analysis for shell invocation, command concatenation, and user-controlled values reaching process execution APIs
- Code review checks for route parameters used in formatted command strings
- Tests using malformed and boundary-value route inputs to verify strict rejection and correct type handling
- Web application firewall or gateway policies monitoring unexpected shell metacharacters in administrative parameters
- Runtime monitoring for unusual process creation, command execution, or route changes originating from the management service
- Automated security review tools that identify command-injection data flows during development
Sources
| Source | Link |
|---|---|
| github. | github.com/ |
| vuldb. | vuldb.com/ |
| vuldb. | vuldb.com/ |
| vuldb. | vuldb.com/ |
| vuldb. | vuldb.com/ |
| linksys. | linksys.com/ |
