External risk intelligence

Apple Operating Systems: Code Execution Risk

CVE advisoryKnown Exploit

CVE-2021-1871

This vulnerability affects WebKit, a core component used by browsers and applications to render web content. While it is plausibly reachable when a user visits malicious or compromised websites via a browser, it is not a server-side, internet-facing service or appliance portal that is exposed by design for external access.

Apple Ipados

before 14.410.15 to before 10.15.710.15.711.0.1 to before 11.210.033

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A logic issue within Apple's operating systems could allow unauthorized code execution. This vulnerability affects the WebKit component, which is used for rendering web content. An attacker could potentially leverage this flaw to compromise systems.

Vulnerable component: WebKit
Core weakness: Logic issue
Main business impact: Arbitrary code execution

Attack Path

How an attacker could exploit the issue

A logic flaw in WebKit could allow an attacker to execute arbitrary code. This vulnerability could affect organizations that use affected Apple products or software relying on the WebKit rendering engine. Apple has confirmed awareness of reports indicating this issue may have been actively exploited.

Exposure condition: Network access.
Attacker starting point: No authentication needed.
Trigger and result: Arbitrary code execution.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability presents a significant risk, as it allows for remote code execution, meaning an attacker can run unauthorized code on an affected system without any prior access. The potential for arbitrary code execution can lead to the compromise of sensitive data, disruption of business operations, and the installation of further malicious software. Given that the issue has been actively exploited, organizations should prioritize addressing this vulnerability to mitigate potential business risk.

Attackers with general skill.
No access or conditions needed.
High business risk or urgency.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in the system's core web rendering engine could allow a remote attacker to execute arbitrary code. Organizations should prioritize addressing this issue to mitigate potential business risk.

Identify all affected systems and devices.
Reduce exposure by isolating risk.
Apply vendor fixes and validate the update.
Monitor for related issues.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is CVE-2021-1871 and which Apple systems does it affect?

CVE-2021-1871 is a vulnerability found in Apple's WebKit, the engine used by browsers like Safari to display web content. It impacts iOS, iPadOS, and macOS systems prior to specific updates. This flaw could enable attackers to execute arbitrary code on vulnerable devices, meaning they might run unauthorized programs.

What type of weakness does CVE-2021-1871 represent and how is it triggered?

The vulnerability is characterized as a logic issue within WebKit, indicating a flaw in how the software processes certain operations. Exploiting this weakness could allow a remote attacker to execute arbitrary code, potentially leading to system compromise without needing any prior access or authentication.

What is the scope of impact for CVE-2021-1871?

This vulnerability affects the WebKit component, a critical part of Apple's operating systems used for rendering web content. Its scope includes systems that utilize WebKit, such as Safari, and potentially other non-Apple products relying on this engine for HTML processing. The exposure is considered external as it can be triggered over a network.

What is the relevance of CVE-2021-1871, considering its exploitation status?

CVE-2021-1871 is relevant due to its potential for remote code execution, a high-risk scenario where an attacker can run unauthorized code on a system. Apple has acknowledged reports that this vulnerability may have been actively exploited in the wild. This active exploitation elevates the business risk and urgency for remediation.

How should organizations respond to CVE-2021-1871?

Organizations should prioritize addressing this vulnerability by identifying all affected systems, reducing exposure through isolation where possible, and applying vendor-provided fixes. Verifying the successful application of updates and monitoring for any related suspicious activity are crucial steps in mitigating potential business risks.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.