CyberSecBulletin
CVE-2023-42947NVD status: Modified

iOS and iPadOS: Improper Limitation of a Pathname to a Restricted Directory

Published Updated By the CyberSecBulletin desk

CVE-2023-42947 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in iOS and iPadOS from Apple, with a CVSS 3.1 base score of 8.6 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 17.2 as the first without the flaw, so updating iOS and iPadOS to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.25% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update iOS and iPadOS to 17.2 or a later version.
  2. Update macOS to 13.6 or 12.7 or 14.2, whichever matches your release line, or a later version.
  3. Update tvOS to 17.2 or a later version.
  4. Read the advisory on support.apple.com for workarounds and exact fixed builds.
  5. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
AppleiOS and iPadOSbefore 17.217.2
ApplemacOSbefore 13.6; before 12.7; before 14.213.6, 12.7, 14.2
AppletvOSbefore 17.217.2
ApplewatchOSbefore 10.210.2
AppleiPadOSbefore 17.217.2
AppleIphone OSbefore 17.217.2

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
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
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:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.6HighNVD
CVSS 3.18.6HighCISA (ADP)

Official description

A path handling issue was addressed with improved validation. This issue is fixed in macOS Monterey 12.7.2, macOS Ventura 13.6.3, iOS 17.2 and iPadOS 17.2, tvOS 17.2, watchOS 10.2, macOS Sonoma 14.2. An app may be able to break out of its sandbox.

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

The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

How developers prevent this class of flaw

  • 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.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
  • Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.

More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in iOS and iPadOS

All iOS and iPadOS vulnerabilities

Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities

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