External risk intelligence

Apple iOS Memory Corruption Vulnerability.

CVE advisoryKnown Exploit

CVE-2021-30761

This vulnerability involves processing maliciously crafted web content within the iOS environment. While web browsers and content processors are common targets, the vulnerability requires a user to interact with specific, malicious web content, making internet exposure possible but dependent on user behavior rather than being an inherently exposed internet-facing service or appliance.

Out-of-bounds Write

Apple Iphone Os

before 12.5.4

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

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A memory corruption issue in web content processing could allow for arbitrary code execution. This vulnerability is present in Apple's iPhone operating system. When exploited, it may lead to significant business risk by enabling unauthorized code execution.

  • Vulnerable web content processing
  • Memory corruption flaw
  • Arbitrary code execution impact

Attack Path

How an attacker could exploit the issue

An attacker can exploit a memory corruption vulnerability in WebKit by directing an organization's users to a malicious website. This allows the attacker to execute arbitrary code on the user's device, potentially leading to unauthorized access to sensitive data or system control. The vulnerability is a result of improper state management when processing web content.

  • Exposure through web content
  • Attacker directs users to malicious site
  • Triggering code execution and impact

Live Threat

Current exploitation, exposure, and threat context

A memory corruption vulnerability in Apple's iOS could allow for arbitrary code execution. This occurs when processing specially crafted web content, and there are reports that this issue has been actively exploited. Organizations should consider the potential impact on their employee devices and associated data.

  • Attacker skill: Low
  • Access needed: User interaction with malicious content
  • Business risk: High, active exploitation reported

Operational Fix

Recommended remediation, mitigation, and detection steps

The organization should address a memory corruption vulnerability that could allow attackers to execute arbitrary code by processing malicious web content. Apple has indicated awareness of reports suggesting this vulnerability may have been actively exploited. Prompt action is recommended to mitigate potential business risk to affected systems and data.

  • Identify affected iOS devices.
  • Reduce exposure or isolate risk.
  • Apply vendor fix, verify, and monitor.

Supplementary metadata

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.

Frequently asked questions

What is iOS and its purpose?

iOS is the mobile operating system developed by Apple for its iPhone and iPad devices. It provides the software foundation for all device functions and applications, enabling a consistent and secure user experience. iOS is known for its intuitive interface and strong integration with other Apple products.

What is CVE-2021-30761 and its weakness?

CVE-2021-30761 is a critical memory corruption vulnerability within Apple's iOS, specifically in the WebKit engine. This weakness is classified as CWE-787 (Out-of-Bounds Write). It can be triggered when the system processes specially crafted web content.

How can CVE-2021-30761 be exploited?

Exploitation of CVE-2021-30761 occurs when a user is directed to a malicious website. The vulnerability allows for arbitrary code execution on the affected iOS device by processing this crafted web content, bypassing standard security measures for content handling.

What is the relevance of CVE-2021-30761?

CVE-2021-30761 presents a significant risk because it has been reported as actively exploited. This memory corruption vulnerability in iOS's WebKit could allow attackers to gain control of a device through malicious web content, potentially leading to unauthorized access or data compromise.

What actions should be taken for CVE-2021-30761?

To address CVE-2021-30761, organizations should identify all affected iOS devices and apply the necessary vendor updates, specifically iOS 12.5.4. It is crucial to verify that the patch has been successfully implemented and to monitor systems for any unusual activity that might indicate a compromise.

References