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Arbitrary remote code execution within `wrangler dev` Workers sandbox

Critical severity GitHub Reviewed Published Dec 29, 2023 in cloudflare/workers-sdk • Updated Jan 3, 2024

Package

npm wrangler (npm)

Affected versions

>= 3.0.0, < 3.19.0
>= 2.0.0, < 2.20.2

Patched versions

3.19.0
2.20.2

Description

Impact

The V8 inspector intentionally allows arbitrary code execution within the Workers sandbox for debugging. wrangler dev would previously start an inspector server listening on all network interfaces. This would allow an attacker on the local network to connect to the inspector and run arbitrary code. Additionally, the inspector server did not validate Origin/Host headers, granting an attacker that can trick any user on the local network into opening a malicious website the ability to run code. If wrangler dev --remote was being used, an attacker could access production resources if they were bound to the worker.

Patches

This issue was fixed in [email protected] and [email protected]. Whilst wrangler dev's inspector server listens on local interfaces by default as of [email protected], an SSRF vulnerability in miniflare allowed access from the local network until [email protected]. [email protected] and [email protected] introduced validation for the Origin/Host headers.

Workarounds

Unfortunately, Wrangler doesn't provide any configuration for which host that inspector server should listen on. Please upgrade to at least [email protected], and configure Wrangler to listen on local interfaces instead with wrangler dev --ip 127.0.0.1 to prevent SSRF. This removes the local network as an attack vector, but does not prevent an attack from visiting a malicious website.

References

References

@mskowroncf mskowroncf published to cloudflare/workers-sdk Dec 29, 2023
Published by the National Vulnerability Database Dec 29, 2023
Published to the GitHub Advisory Database Jan 3, 2024
Reviewed Jan 3, 2024
Last updated Jan 3, 2024

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
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
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:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

EPSS score

0.053%
(23rd percentile)

Weaknesses

CVE ID

CVE-2023-7080

GHSA ID

GHSA-f8mp-x433-5wpf

Source code

Credits

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