CVE-2024-22197: Authenticated (user role) remote command execution by modifying `nginx` settings (GHSL-2023-269)

The Home > Preference page exposes a small list of nginx settings such as Nginx Access Log Path and Nginx Error Log Path. However, the API also exposes test_config_cmd, reload_cmd and restart_cmd. While the UI doesn’t allow users to modify any of these settings, it is possible to do so by sending a request to the API.

func InitPrivateRouter(r *gin.RouterGroup) {
r.GET("settings", GetSettings)
r.POST("settings", SaveSettings)
...
}

The SaveSettings function is used to save the settings. It is protected by the authRequired middleware, which requires a valid JWT token or a X-Node-Secret which must equal the Node Secret configuration value. However, given the lack of authorization roles, any authenticated user can modify the settings. The SaveSettings function is defined as follows:

func SaveSettings(c *gin.Context) {
var json struct {
...
Nginx  settings.Nginx  `json:"nginx"`
...
}

...

settings.NginxSettings = json.Nginx

...

err := settings.Save()
...
}

The test_config_cmd setting is stored as settings.NginxSettings.TestConfigCmd. When the application wants to test the nginx configuration, it uses the TestConf function:

func TestConf() (out string) {
if settings.NginxSettings.TestConfigCmd != "" {
out = execShell(settings.NginxSettings.TestConfigCmd)

return
}

out = execCommand("nginx", "-t")

return
}

The execShell function is defined as follows:

func execShell(cmd string) (out string) {
bytes, err := exec.Command("/bin/sh", "-c", cmd).CombinedOutput()
out = string(bytes)
if err != nil {
out += " " + err.Error()
}
return
}

Where the cmd argument is user-controlled and is passed to /bin/sh -c. This issue was found using CodeQL for Go: Command built from user-controlled sources.