GHSA-fgxv-gw55-r5fq
Authorization Bypass Through User-Controlled Key in go-zero
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Go | github.com/zeromicro/go-zero | < 1.4.4 | 1.4.4 |
Details
As written in the advisory (Markdown source, shown as plain text).
### Summary
Hello go-zero maintainer team, I would like to report a security concerning your CORS Filter feature.
### Details
Go-zero allows user to specify a [CORS Filter](https://github.com/zeromicro/go-zero/blob/master/rest/internal/cors/handlers.go) with a configurable allows param - which is an array of domains allowed in CORS policy.
However, the `isOriginAllowed` uses `strings.HasSuffix` to check the origin, which leads to bypass via domain like `evil-victim.com`
```go
func isOriginAllowed(allows []string, origin string) bool {
for _, o := range allows {
if o == allOrigins {
return true
}
if strings.HasSuffix(origin, o) {
return true
}
}
return false
}
```
### PoC
Use code below as a PoC. Only requests from `safe.com` should bypass the CORS Filter
```go
package main
import (
"errors"
"net/http"
"github.com/zeromicro/go-zero/rest"
)
func main() {
svr := rest.MustNewServer(rest.RestConf{Port: 8888}, rest.WithRouter(mockedRouter{}), rest.WithCors("safe.com"))
svr.Start()
}
type mockedRouter struct{}
// some sensitive path
func (m mockedRouter) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// check user's cookie
// ...
// return sensitive data
w.Write([]byte("social_id: 420101198008292930"))
}
func (m mockedRouter) Handle(_, _ string, handler http.Handler) error {
return errors.New("foo")
}
func (m mockedRouter) SetNotFoundHandler(_ http.Handler) {
}
func (m mockedRouter) SetNotAllowedHandler(_ http.Handler) {
}
```
Send a request to localhost:8888 with `Origin:not-safe.com`
You can see the origin reflected in response, which bypass the CORS Filter
### Impact
This vulnerability is capable of breaking CORS policy and thus allowing any page to make requests, retrieve data on behalf of other users.
References
External links from the advisory. They lead to third-party sites.