Summary
A command injection vulnerability in the TOTOLINK A950RG firmware affects the apmib_set function in firewall.so. A remote attacker who can supply crafted input to an exposed processing path may cause operating-system commands to be executed with the privileges of the affected service.
A command injection vulnerability in the TOTOLINK A950RG firmware affects the apmib_set function in firewall.so. A remote attacker who can supply crafted input to an exposed processing path may cause operating-system commands to be executed with the privileges of the affected service.
Affected context
The issue occurs in TOTOLINK A950RG firmware version 4.1.2cu.5268_B20221104, where the apmib_set function in the firewall.so component processes externally influenced data. Risk depends on whether a remotely reachable management or network-service path passes attacker-controlled values to this function and whether authentication, network segmentation, or other access controls limit that path.
The issue occurs in TOTOLINK A950RG firmware version 4.1.2cu.5268_B20221104, where the apmib_set function in the firewall.so component processes externally influenced data. Risk depends on whether a remotely reachable management or network-service path passes attacker-controlled values to this function and whether authentication, network segmentation, or other access controls limit that path.
Exploit preconditions
- Attack surface: A remotely reachable router service or management interface
that invokes the affected firewall.so functionality
- Required access: Network access to the relevant service; authentication
requirements depend on the exposed interface and deployment configuration
- Trigger point: Processing of attacker-influenced input by the apmib_set
function
- Why exploitation is possible: Input may reach a command execution context
without adequate separation, validation, or neutralization of shell
metacharacters
- Attack surface: A remotely reachable router service or management interface
that invokes the affected firewall.so functionality
- Required access: Network access to the relevant service; authentication
requirements depend on the exposed interface and deployment configuration
- Trigger point: Processing of attacker-influenced input by the apmib_set
function
- Why exploitation is possible: Input may reach a command execution context
without adequate separation, validation, or neutralization of shell
metacharacters
Why this happens
The underlying flaw is a command injection condition in which data intended as configuration or parameter content is incorporated into an operating-system command context. If command construction does not enforce strict allowlisting and safe argument handling, attacker-controlled separators or operators can alter the intended command. This maps directly to CWE-77, with CWE-74 representing the broader class of improper neutralization of special elements in output used by a downstream interpreter.
The underlying flaw is a command injection condition in which data intended as configuration or parameter content is incorporated into an operating-system command context. If command construction does not enforce strict allowlisting and safe argument handling, attacker-controlled separators or operators can alter the intended command. This maps directly to CWE-77, with CWE-74 representing the broader class of improper neutralization of special elements in output used by a downstream interpreter.
Potential impact
- An attacker may execute arbitrary commands on the router.
- The device could be taken over or rendered unavailable.
- Network traffic, credentials, or configuration data could be exposed.
- The router could be used to attack other internal systems.
- Persistent manipulation of firewall or routing settings could occur.
- An attacker may execute arbitrary commands on the router.
- The device could be taken over or rendered unavailable.
- Network traffic, credentials, or configuration data could be exposed.
- The router could be used to attack other internal systems.
- Persistent manipulation of firewall or routing settings could occur.
General mitigation guidance
Mitigation generally focuses on eliminating shell interpretation of attacker-influenced data. Secure-by-default alternatives include direct library or system APIs that pass arguments as structured values rather than concatenated command strings. Inputs should be reduced to trusted, allowlisted values and validated before use, while escaping alone should not be treated as the primary control. Administrative interfaces should be limited to trusted networks, and router services should run with the minimum privileges required. Defense-in-depth controls may include segmentation, restricted management access, immutable configuration where practical, and monitoring for unexpected process or configuration changes.
Mitigation generally focuses on eliminating shell interpretation of attacker-influenced data. Secure-by-default alternatives include direct library or system APIs that pass arguments as structured values rather than concatenated command strings. Inputs should be reduced to trusted, allowlisted values and validated before use, while escaping alone should not be treated as the primary control. Administrative interfaces should be limited to trusted networks, and router services should run with the minimum privileges required. Defense-in-depth controls may include segmentation, restricted management access, immutable configuration where practical, and monitoring for unexpected process or configuration changes.
How teams detect issues like this
Detection can include static analysis for shell execution APIs, string concatenation or formatting used to build commands, and data flows from network parameters into process-launch functions. Code review should examine firewall and configuration handlers for missing allowlists, unsafe argument construction, and reliance on incomplete escaping. Runtime monitoring can alert on unexpected child processes, command interpreters, or changes to firewall and routing configuration. Automated security review tools and policy checks can help enforce bans on unsafe command construction patterns.
Detection can include static analysis for shell execution APIs, string concatenation or formatting used to build commands, and data flows from network parameters into process-launch functions. Code review should examine firewall and configuration handlers for missing allowlists, unsafe argument construction, and reliance on incomplete escaping. Runtime monitoring can alert on unexpected child processes, command interpreters, or changes to firewall and routing configuration. Automated security review tools and policy checks can help enforce bans on unsafe command construction patterns.
Sources
| Source | Link |
|---|---|
| gist. | gist.github.com/ |
| vuldb. | vuldb.com/ |
| vuldb. | vuldb.com/ |
| vuldb. | vuldb.com/ |
| vuldb. | vuldb.com/ |
| totolink. | totolink.net/ |
