CyberSecBulletin
CVE-2021-1782Exploited in the wildNVD status: Analyzed

Apple Multiple Products Race Condition

Published Updated By the CyberSecBulletin desk

CVE-2021-1782 is a high-severity improper locking vulnerability in iOS and iPadOS from Apple, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version 14.4 as the first without the flaw, so updating iOS and iPadOS to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update iOS and iPadOS to 14.4 or a later version.
  2. Update macOS to 11.2 or 7.3 or 14.4, whichever matches your release line, or a later version.
  3. Update iPadOS to 14.4 or a later version.
  4. CISA's required action: Apply updates per vendor instructions.
  5. Read the advisory on support.apple.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
AppleiOS and iPadOSbefore 14.414.4
ApplemacOSbefore 11.2; before 7.3; before 14.411.2, 7.3, 14.4
AppleiPadOSbefore 14.414.4
AppleIphone OSbefore 14.414.4
AppleMac OS X10.14 up to, but not including, 10.14.6; 10.15 up to, but not including, 10.15.7; 10.14.6; 10.15.710.14.6, 10.15.7
AppletvOSbefore 14.414.4
ApplewatchOSbefore 7.37.3

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
HighSuccess depends on conditions outside the attacker's control.
Privileges required
LowA basic user account is enough.
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:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.0HighNVD
CVSS 3.17.0HighCISA (ADP)
CVSS 2.06.9MediumNVD

Official description

A race condition was addressed with improved locking. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. A malicious application may be able to elevate privileges. Apple is aware of a report that this issue may have been actively exploited..

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

The underlying weakness: Improper Locking

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

How developers prevent this class of flaw

  • Use industry standard APIs to implement locking mechanism.

More Improper Locking vulnerabilities (CWE-667)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
  5. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in iOS and iPadOS

All iOS and iPadOS vulnerabilities

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