CyberSecBulletin
CVE-2023-1862NVD status: Modified

WARP Client: Improper Access Control

Published Updated By the CyberSecBulletin desk

CVE-2023-1862 is a high-severity improper access control vulnerability in WARP Client from Cloudflare, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 2023.3.381.0 as the first without the flaw, so updating WARP Client to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.75% chance of exploitation within 30 days, higher than 56% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update WARP Client to 2023.3.381.0 or a later version.
  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
CloudflareWARP Clientbefore 2023.3.381.02023.3.381.0
CloudflareWarp2023.3.381.0 and earlierNot 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
LowSome restricted data can be read.
Integrity
LowLimited modification of data is possible.
Availability
LowPerformance or availability is reduced.

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

Scoring systemScoreSeverityScored by
CVSS 3.17.3HighCNA (cloudflare.com)
CVSS 3.17.3HighNVD

Official description

Cloudflare WARP client for Windows (up to v2023.3.381.0) allowed a malicious actor to remotely access the warp-svc.exe binary due to an insufficient access control policy on an IPC Named Pipe. This would have enabled an attacker to trigger WARP connect and disconnect commands, as well as obtaining network diagnostics and application configuration from the target's device. It is important to note that in order to exploit this, a set of requirements would need to be met, such as the target's device must've been reachable on port 445, allowed authentication with NULL sessions or otherwise having knowledge of the target's credentials.

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

The underlying weakness: Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

How developers prevent this class of flaw

  • Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
  • 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 Improper Access Control vulnerabilities (CWE-284)

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

Recent Improper Access Control vulnerabilities

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