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Static imports inside dynamically imported modules do not adhere to permission checks

Critical
lucacasonato published GHSA-xpwj-7v8q-mcgj May 20, 2021

Package

cargo deno (Rust)

Affected versions

1.5.0 - 1.10.1

Patched versions

1.10.2

Description

Impact

Modules that are dynamically imported through import() or new Worker might have been able to bypass network and file system permission checks when statically importing other modules. In Deno 1.5.x and 1.6.x only programs dynamically importing (especially transitively) untrusted code are affected. In Deno 1.7.x all programs importing (especially transitively) untrusted code are affected.

In effect an attacker in control of a (possibly remote) module in a programs module graph has been able to, irrespective of permissions:

  1. initiate GET requests to arbitrary URLs on the internet (including LAN) and possibly read (parts of) the contents of these resources.
  2. check for existence of arbitrary paths on the file system, and possibly read (parts of) the contents of these files.

In Deno 1.5.x (October 27th, 2020) and Deno 1.6.x (December 8th, 2020) the attacker module had to have been granted permissions to load dynamically through the network / fs read permission. Since Deno 1.7.x (January 19th, 2021) this vulnerability was able to be exploited in a fully sandboxed isolate (without any permissions). This vulnerability was not present in releases prior to 1.5.0.

Arbitrary non-GET requests, control over request headers, or file system writes are not possible through this vulnerability. Users of the deno_core, deno_runtime, or other deno_* crates are not affected. This is a Deno CLI only vulnerability.

We are relatively confident this was not abused in the wild, as by default Deno prints out a green "Download" message when remote imports are downloaded, and this would have caused suspicion if it occurred in the middle of a programs execution. This message can be silenced with the --quiet flag.

Patches

The vulnerability has been patched in Deno release 1.10.2. You can upgrade to the latest Deno version by running the deno upgrade command. The release is available through all official download channels.

Workarounds

There is no workaround for this issue.

For more information

If you have any questions or comments about this advisory:

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVE ID

CVE-2021-32619

Weaknesses

Credits