CyberSecBulletin
CVE-2022-39327NVD status: Modified

azure-cli: Improper Neutralization of Special Elements used in an OS Command

CVE-2022-39327 is a critical-severity improper neutralization of special elements used in an OS command vulnerability in azure-cli from Azure, 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 azure-cli versions: < 2.40.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 4.24% chance of exploitation within 30 days, which is in the top 8.82% of all scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Azure Command-line Interface to 2.40.0 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
Azureazure-cli< 2.40.0Not stated
MicrosoftAzure Command-line Interfacebefore 2.40.02.40.0

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 3.18.1HighCNA (github.com)
CVSS 3.19.8CriticalNVD

Official description

Azure CLI is the command-line interface for Microsoft Azure. In versions previous to 2.40.0, Azure CLI contains a vulnerability for potential code injection. Critical scenarios are where a hosting machine runs an Azure CLI command where parameter values have been provided by an external source. The vulnerability is only applicable when the Azure CLI command is run on a Windows machine and with any version of PowerShell and when the parameter value contains the `&` or `|` symbols. If any of these prerequisites are not met, this vulnerability is not applicable. Users should upgrade to version 2.40.0 or greater to receive a a mitigation for the vulnerability.

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

The underlying weakness: Improper Neutralization of Special Elements used in an OS Command

The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.

How developers prevent this class of flaw

  • If at all possible, use library calls rather than external processes to recreate the desired functionality.
  • For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.
  • For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

More Improper Neutralization of Special Elements used in an OS Command vulnerabilities (CWE-78)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Advisories

Patches and release notes

Recent Improper Neutralization of Special Elements used in an OS Command vulnerabilities

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