CyberSecBulletin
CVE-2023-33966NVD status: Modified

deno: Incorrect Default Permissions

CVE-2023-33966 is a critical-severity incorrect default permissions vulnerability in deno from Denoland, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected deno versions: deno = 1.34.0; deno_runtime = 0.114.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.63% chance of exploitation within 30 days, higher than 51% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of deno you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Denolanddenodeno = 1.34.0; deno_runtime = 0.114.0Not stated
DenoDeno Runtime0.114.0Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.6HighCNA (github.com)
CVSS 3.19.8CriticalNVD

Official description

Deno is a runtime for JavaScript and TypeScript. In deno 1.34.0 and deno_runtime 0.114.0, outbound HTTP requests made using the built-in `node:http` or `node:https` modules are incorrectly not checked against the network permission allow list (`--allow-net`). Dependencies relying on these built-in modules are subject to the vulnerability too. Users of Deno versions prior to 1.34.0 are unaffected. Deno Deploy users are unaffected. This problem has been patched in Deno v1.34.1 and deno_runtime 0.114.1 and all users are recommended to update to this version. No workaround is available for this issue.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Incorrect Default Permissions

During installation, installed file permissions are set to allow anyone to modify those files.

How developers prevent this class of flaw

  • The architecture needs to access and modification attributes for files to only those users who actually require those actions.
  • Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

More Incorrect Default Permissions vulnerabilities (CWE-276)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Patches and release notes

Other vulnerabilities in deno

All deno vulnerabilities

Recent Incorrect Default Permissions vulnerabilities

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