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CRITICAL9.1

GHSA-fgxv-gw55-r5fq

Authorization Bypass Through User-Controlled Key in go-zero

Quick fix

GHSA-fgxv-gw55-r5fq — github.com/zeromicro/go-zero: upgrade to the fixed version with the command below.

go get github.com/zeromicro/go-zero@v1.4.4

Details

### 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 ![image](https://user-images.githubusercontent.com/70683161/221365842-9d76a3a4-a79d-413a-85b7-06b50b0a7807.png)

### Impact This vulnerability is capable of breaking CORS policy and thus allowing any page to make requests, retrieve data on behalf of other users.

Are you affected?

Enter the version of the package you're using.

Affected packages

Go/github.com/zeromicro/go-zero
Introduced in: 0Fixed in: 1.4.4
Fixgo get github.com/zeromicro/go-zero@v1.4.4

References