iOS and iPadOS: Improper Link Resolution Before File Access
CVE-2023-42942 is a high-severity improper link resolution before file access vulnerability in iOS and iPadOS from Apple, with a CVSS 3.1 base score of 7.8 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 versions 16.7, 17.1 as the first without the flaw, so updating iOS and iPadOS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.39% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update iOS and iPadOS to 16.7 or 17.1, whichever matches your release line, or a later version.
- Update tvOS to 17.1 or a later version.
- Update macOS to 14.1 or 13.6 or 13.6.1, whichever matches your release line, or a later version.
- Read the advisory on support.apple.com for workarounds and exact fixed builds.
- 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
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apple | iOS and iPadOS | before 16.7; before 17.1 | 16.7, 17.1 |
| Apple | tvOS | before 17.1 | 17.1 |
| Apple | macOS | before 14.1; before 13.6; 14.0 up to, but not including, 14.1; before 13.6.1 | 14.1, 13.6, 13.6.1 |
| Apple | watchOS | before 10.1 | 10.1 |
| Apple | iphone_os | before 16.7; 17.0 up to, but not including, 17.1 | 16.7, 17.1 |
| Apple | ipad_os | before 16.7; 17.0 up to, but not including, 17.1 | 16.7, 17.1 |
| Apple | iPadOS | 17.0 | Not 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
- 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
- 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:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
This issue was addressed with improved handling of symlinks. This issue is fixed in watchOS 10.1, macOS Sonoma 14.1, tvOS 17.1, iOS 16.7.2 and iPadOS 16.7.2, iOS 17.1 and iPadOS 17.1, macOS Ventura 13.6.1. A malicious app may be able to gain root privileges.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Link Resolution Before File Access
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
How developers prevent this class of flaw
- Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
More Improper Link Resolution Before File Access vulnerabilities (CWE-59)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other references
Other vulnerabilities in iOS and iPadOS
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Link Resolution Before File Access vulnerabilities
- 7.1 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.