Patchfirst
CVE-2021-1871 KEV Critical · 9.8 EPSS 7.0%

Apple iOS, iPadOS, and macOS WebKit Remote Code Execution Vulnerability

Apple · iOS, iPadOS, and macOS

Summary

A logic flaw in WebKit, the browser engine shipped in Apple's iOS, iPadOS, and macOS, lets web content bypass restrictions that should have been enforced. A remote attacker can exploit it without authentication or user interaction over the network to achieve arbitrary code execution.

Official description · NVD

A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, iOS 14.4 and iPadOS 14.4. A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

Breakdown
60.7 / 100
Exploited
Yes, in CISA KEV
Reports
0
Tactics
2/15

How an attack unfolds

Based on mappings. Select a step to see the evidence.
  1. How attackers get in

  2. What they do

First seen exploited 2 months before it was disclosed.

  1. First seen exploitedVulnCheck KEV evidence2 mo before
  2. Disclosedday 0
  3. Added to CISA KEVEU database agrees+7 mo

CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.

techniques

2 , grouped by in kill-chain order, 2 cited passages 2

Initial AccessTA0001

Exploit Public-Facing Application T1190 Medium
AI mapping from the description · how it is exploited

remote attacker exploits public-facing exposure

A remote attacker may be able to cause arbitrary code execution
From the official description (NVD) Original (opens in a new tab) ↗

ExecutionTA0002

Command and Scripting Interpreter T1059 Medium
AI mapping from the description · primary impact

direct arbitrary code execution impact

A remote attacker may be able to cause arbitrary code execution
From the official description (NVD) Original (opens in a new tab) ↗

Detection

0 rules for this CVE · 244 general rules for its techniques

Rules for this CVE

0 that reference CVE-2021-1871 directly.

CVE-specific rules are not available in this build. Search SigmaHQ ↗

Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.

What security researchers reported

Not named in any threat report yet

References

5 links, grouped by NVD tag (4 duplicates merged)
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