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Information disclosure in AccessControl

Moderate severity GitHub Reviewed Published Sep 6, 2023 in zopefoundation/AccessControl • Updated Nov 6, 2023

Package

pip AccessControl (pip)

Affected versions

< 4.4
>= 5.0, < 5.8
>= 6.0, < 6.2

Patched versions

4.4
5.8
6.2
pip Zope (pip)
< 4.8.9
>= 5.0.0, < 5.8.4
4.8.9
5.8.4

Description

Impact

Python's "format" functionality allows someone controlling the format string to "read" objects accessible (recursively) via attribute access and subscription from accessible objects. Those attribute accesses and subscriptions use Python's full blown getattr and getitem, not the policy restricted AccessControl variants _getattr_ and _getitem_. This can lead to critical information disclosure.

AccessControl already provides a safe variant for str.format and denies access to string.Formatter. However, str.format_map is still unsafe.

Affected are all users who allow untrusted users to create AccessControl controlled Python code and execute it.

Patches

A fix will be introduced in the versions 4.4, 5.8 and 6.2.

Workarounds

There are no workarounds.

References

GHSA-xjw2-6jm9-rf67 describes the corresponding problem for RestrictedPython.

References

@dataflake dataflake published to zopefoundation/AccessControl Sep 6, 2023
Published by the National Vulnerability Database Sep 6, 2023
Published to the GitHub Advisory Database Sep 7, 2023
Reviewed Sep 7, 2023
Last updated Nov 6, 2023

Severity

Moderate

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
High
User interaction
None
Scope
Changed
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:H/UI:N/S:C/C:H/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(41st percentile)

Weaknesses

Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Learn more on MITRE.

CVE ID

CVE-2023-41050

GHSA ID

GHSA-8xv7-89vj-q48c

Source code

Credits

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