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Sandbox escape via various forms of "format".

High severity GitHub Reviewed Published Aug 30, 2023 in zopefoundation/RestrictedPython • Updated Nov 7, 2023

Package

pip RestrictedPython (pip)

Affected versions

<= 5.3
>= 6.0, <= 6.1

Patched versions

5.4
6.2

Description

Impact

Python's "format" functionality allows someone controlling the format string to "read" all objects accessible through recursive attribute lookup and subscription from objects he can access. This can lead to critical information disclosure.
With RestrictedPython, the format functionality is available via the format and format_map methods of str (and unicode) (accessed either via the class or its instances) and via string.Formatter.
All known versions of RestrictedPython are vulnerable.

Patches

The issue will be fixed in 5.4 and 6.2.

Workarounds

There are no workarounds to fix the issue without upgrading.

References

For more information

If you have any questions or comments about this advisory:

Credits

Thanks for analysing and reporting the go to:

  • Abhishek Govindarasu
  • Ankush Menat
  • Ward Theunisse

References

@icemac icemac published to zopefoundation/RestrictedPython Aug 30, 2023
Published by the National Vulnerability Database Aug 30, 2023
Published to the GitHub Advisory Database Aug 30, 2023
Reviewed Aug 30, 2023
Last updated Nov 7, 2023

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
High
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
Low

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:R/S:C/C:H/I:H/A:L

EPSS score

0.071%
(33rd percentile)

Weaknesses

CVE ID

CVE-2023-41039

GHSA ID

GHSA-xjw2-6jm9-rf67

Source code

Credits

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