Summary
A command injection vulnerability in the DrayTek Vigor2960 IPsec Handler allows attacker-controlled input in the option argument to influence operating-system command processing. Because the affected CGI function is remotely reachable, an attacker who can access the relevant endpoint may execute commands with the privileges of the web service.
A command injection vulnerability in the DrayTek Vigor2960 IPsec Handler allows attacker-controlled input in the option argument to influence operating-system command processing. Because the affected CGI function is remotely reachable, an attacker who can access the relevant endpoint may execute commands with the privileges of the web service.
Affected context
The issue occurs in the ruequest_certificate function within /cgi-bin/mainfunction.cgi, which is associated with the IPsec Handler. It becomes risky when the CGI endpoint is reachable over a network and the option parameter is incorporated into command execution without sufficiently separating data from operating-system instructions. The affected product is an end-of-support device with limited ongoing security review.
The issue occurs in the ruequest_certificate function within /cgi-bin/mainfunction.cgi, which is associated with the IPsec Handler. It becomes risky when the CGI endpoint is reachable over a network and the option parameter is incorporated into command execution without sufficiently separating data from operating-system instructions. The affected product is an end-of-support device with limited ongoing security review.
Exploit preconditions
- Attack surface: The remotely reachable CGI interface used by the IPsec Handler
- Required access: Network access to the affected endpoint; the description does not establish whether authentication is required
- Trigger point: Processing of the
optionargument byruequest_certificate - Why exploitation is possible: User-controlled input reaches an operating-system command execution path without adequate command and argument separation
- Attack surface: The remotely reachable CGI interface used by the IPsec Handler
- Required access: Network access to the affected endpoint; the description does not establish whether authentication is required
- Trigger point: Processing of the
optionargument byruequest_certificate - Why exploitation is possible: User-controlled input reaches an operating-system command execution path without adequate command and argument separation
Why this happens
The underlying bug is a failure to treat request data as untrusted data before it reaches a command interpreter or operating-system command construction routine. When input is concatenated into a command or otherwise passed through an unsafe execution path, control characters or command syntax may alter the intended operation. This maps primarily to CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection'), with CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection') describing the more specific command-processing weakness.
The underlying bug is a failure to treat request data as untrusted data before it reaches a command interpreter or operating-system command construction routine. When input is concatenated into a command or otherwise passed through an unsafe execution path, control characters or command syntax may alter the intended operation. This maps primarily to CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection'), with CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection') describing the more specific command-processing weakness.
Potential impact
- An attacker may execute arbitrary commands on the device
- The attacker could alter network, VPN, or system configuration
- Device credentials, secrets, or traffic-related information may be exposed
- The device may be used for persistence, disruption, or movement toward connected networks
- Availability and integrity of IPsec services may be affected
- An attacker may execute arbitrary commands on the device
- The attacker could alter network, VPN, or system configuration
- Device credentials, secrets, or traffic-related information may be exposed
- The device may be used for persistence, disruption, or movement toward connected networks
- Availability and integrity of IPsec services may be affected
General mitigation guidance
Mitigation generally focuses on removing shell interpretation from request-processing paths and reducing the trust placed in externally supplied parameters.
Common defensive patterns include:
- Prefer direct APIs that pass fixed argument arrays to processes rather than invoking a shell
- Apply strict allowlist validation for operation selectors such as
option - Keep command names and privileged arguments separate from user-controlled values
- Run CGI and management components with the minimum required privileges
- Restrict administrative interfaces to trusted management networks and disable unnecessary exposure
- Apply compensating network controls when legacy or unsupported appliances cannot be changed
Mitigation generally focuses on removing shell interpretation from request-processing paths and reducing the trust placed in externally supplied parameters.
Common defensive patterns include:
- Prefer direct APIs that pass fixed argument arrays to processes rather than invoking a shell
- Apply strict allowlist validation for operation selectors such as
option - Keep command names and privileged arguments separate from user-controlled values
- Run CGI and management components with the minimum required privileges
- Restrict administrative interfaces to trusted management networks and disable unnecessary exposure
- Apply compensating network controls when legacy or unsupported appliances cannot be changed
How teams detect issues like this
Organizations can look for this weakness through:
- Static analysis rules identifying shell execution, command concatenation, and unsafe process-spawning APIs in CGI handlers
- Code review checks for request parameters flowing into system commands without allowlist validation
- Web application testing that verifies metacharacters and unexpected parameter values are rejected without executing downstream operations
- Monitoring for anomalous requests to
/cgi-bin/mainfunction.cgi, unusual certificate-related activity, and unexpected child processes spawned by web services - Policy enforcement that prohibits direct shell invocation in internet-facing management components
Automated application-security and firmware-analysis tools may help identify these data-flow patterns.
Organizations can look for this weakness through:
- Static analysis rules identifying shell execution, command concatenation, and unsafe process-spawning APIs in CGI handlers
- Code review checks for request parameters flowing into system commands without allowlist validation
- Web application testing that verifies metacharacters and unexpected parameter values are rejected without executing downstream operations
- Monitoring for anomalous requests to
/cgi-bin/mainfunction.cgi, unusual certificate-related activity, and unexpected child processes spawned by web services - Policy enforcement that prohibits direct shell invocation in internet-facing management components
Automated application-security and firmware-analysis tools may help identify these data-flow patterns.
