Summary
A critical command injection flaw in the DrayTek Vigor2960 CGI interface allows attacker-controlled request arguments to reach operating-system command execution logic.
Because the vulnerable interface can be reached remotely, exploitation may allow an attacker to execute commands on the router and compromise its operation, depending on access controls and deployment exposure.
A critical command injection flaw in the DrayTek Vigor2960 CGI interface allows attacker-controlled request arguments to reach operating-system command execution logic.
Because the vulnerable interface can be reached remotely, exploitation may allow an attacker to execute commands on the router and compromise its operation, depending on access controls and deployment exposure.
Affected context
The issue occurs in the Vigor2960 1.5.1.6 Revision 8218 CGI interface, specifically within the sub_182B0 function in /cgi-bin/mainfunction.cgi. It becomes risky when externally supplied values for usefile, usescript, or option are incorporated into operating-system command processing without sufficiently separating data from commands. Exposure and exploitability may depend on the device's network accessibility and authentication configuration.
The issue occurs in the Vigor2960 1.5.1.6 Revision 8218 CGI interface, specifically within the sub_182B0 function in /cgi-bin/mainfunction.cgi. It becomes risky when externally supplied values for usefile, usescript, or option are incorporated into operating-system command processing without sufficiently separating data from commands. Exposure and exploitability may depend on the device's network accessibility and authentication configuration.
Exploit preconditions
- Attack surface: The remotely reachable CGI interface on the router
- Required access: Network access to the exposed management or web interface; authentication requirements are deployment-dependent
- Trigger point: Processing of the
usefile,usescript, oroptionarguments - Why exploitation is possible: Attacker-controlled input can influence operating-system command construction or execution without adequate command and argument separation
- Attack surface: The remotely reachable CGI interface on the router
- Required access: Network access to the exposed management or web interface; authentication requirements are deployment-dependent
- Trigger point: Processing of the
usefile,usescript, oroptionarguments - Why exploitation is possible: Attacker-controlled input can influence operating-system command construction or execution without adequate command and argument separation
Why this happens
The vulnerability is an OS command injection flaw mapped primarily to CWE-78: Improper Neutralization of Special Elements used in an OS Command. The CGI handler appears to pass request-controlled values into a command execution path without reliably treating them as inert data. This also relates to CWE-77: Improper Neutralization of Special Elements used in a Command, which covers unsafe composition of commands from untrusted input.
The vulnerability is an OS command injection flaw mapped primarily to CWE-78: Improper Neutralization of Special Elements used in an OS Command. The CGI handler appears to pass request-controlled values into a command execution path without reliably treating them as inert data. This also relates to CWE-77: Improper Neutralization of Special Elements used in a Command, which covers unsafe composition of commands from untrusted input.
Potential impact
- An attacker may execute arbitrary commands with the privileges of the CGI service
- The router could be compromised or reconfigured
- Network traffic may be intercepted, redirected, or disrupted
- Credentials, configuration data, or connected-device information could be exposed
- The compromised device could be used for lateral movement or additional attacks
- An attacker may execute arbitrary commands with the privileges of the CGI service
- The router could be compromised or reconfigured
- Network traffic may be intercepted, redirected, or disrupted
- Credentials, configuration data, or connected-device information could be exposed
- The compromised device could be used for lateral movement or additional attacks
General mitigation guidance
Mitigation generally focuses on removing shell interpretation from request-processing paths and reducing the trust placed in CGI parameters.
Common defensive patterns include:
- Prefer direct process APIs with fixed executables and separate argument arrays instead of shell command construction
- Apply strict allowlists and typed validation for file, script, and option values
- Avoid accepting client-controlled paths or executable content where possible
- Enforce authentication, network segmentation, and restricted administrative exposure for device interfaces
- Run service components with the least privileges needed and limit their ability to modify system configuration
- Treat unsupported devices as higher-risk assets and establish compensating monitoring and replacement planning
Mitigation generally focuses on removing shell interpretation from request-processing paths and reducing the trust placed in CGI parameters.
Common defensive patterns include:
- Prefer direct process APIs with fixed executables and separate argument arrays instead of shell command construction
- Apply strict allowlists and typed validation for file, script, and option values
- Avoid accepting client-controlled paths or executable content where possible
- Enforce authentication, network segmentation, and restricted administrative exposure for device interfaces
- Run service components with the least privileges needed and limit their ability to modify system configuration
- Treat unsupported devices as higher-risk assets and establish compensating monitoring and replacement planning
How teams detect issues like this
Organizations can look for command injection risks through:
- Static analysis rules identifying shell execution or command-building APIs fed by CGI parameters
- Code review checks for string concatenation, interpolation, or shell invocation involving request values
- Tests that verify special characters and unexpected arguments are rejected rather than interpreted
- Web application firewall or gateway policies that restrict unneeded CGI endpoints and suspicious parameter patterns
- Device and network monitoring for unusual administrative requests, configuration changes, outbound connections, or process activity
Automated security review tools may help identify unsafe data flows from HTTP parameters into command execution functions.
Organizations can look for command injection risks through:
- Static analysis rules identifying shell execution or command-building APIs fed by CGI parameters
- Code review checks for string concatenation, interpolation, or shell invocation involving request values
- Tests that verify special characters and unexpected arguments are rejected rather than interpreted
- Web application firewall or gateway policies that restrict unneeded CGI endpoints and suspicious parameter patterns
- Device and network monitoring for unusual administrative requests, configuration changes, outbound connections, or process activity
Automated security review tools may help identify unsafe data flows from HTTP parameters into command execution functions.
