CVE-2024-44155 is a vulnerability identified in Apple macOS and Safari browsers that stems from a flaw in the handling of custom URL schemes within iframe sandboxing policies. The iframe sandbox attribute is designed to restrict capabilities of embedded content, preventing malicious web pages from executing unauthorized actions or accessing sensitive data. However, this vulnerability allows specially crafted web content to bypass these sandbox restrictions by exploiting insufficient input validation in the processing of custom URL schemes. This can lead to a violation of the iframe sandbox policy, enabling an attacker to manipulate the integrity of the web content or the browsing context. The vulnerability affects multiple Apple platforms including macOS Sequoia 15, Safari 18, iOS 17.7.1, iPadOS 17.7.1, watchOS 11, and subsequent versions. The CVSS 3.1 score is 6.5 (medium), reflecting that the attack vector is network-based with low attack complexity, no privileges required, but user interaction is necessary to trigger the exploit. The impact is primarily on integrity, with no direct confidentiality or availability loss. Apple has addressed this issue by enhancing input validation mechanisms in the affected components. No known exploits are currently active in the wild, but the vulnerability poses a risk if exploited via malicious web content, such as phishing or drive-by downloads. The fix is included in the latest software updates from Apple, emphasizing the importance of timely patching.

For European organizations, this vulnerability could allow attackers to bypass browser security controls, potentially enabling web-based attacks that alter or manipulate web content integrity. This could facilitate phishing, session hijacking, or injection of malicious scripts within sandboxed iframes, undermining user trust and security. While confidentiality and availability are not directly impacted, the integrity compromise could lead to unauthorized actions or data manipulation in web applications accessed via Safari or other Apple browsers. Organizations relying heavily on Apple devices for critical operations, especially those in finance, government, or healthcare sectors, may face increased risk of targeted web-based attacks exploiting this flaw. The requirement for user interaction means social engineering remains a key attack vector. Additionally, the widespread use of Apple products in Europe, particularly in countries with high technology adoption rates, increases the potential attack surface. Failure to patch could result in increased exposure to sophisticated web attacks that circumvent standard iframe protections.

1. Immediately apply the latest Apple security updates for macOS Sequoia 15, Safari 18, iOS 17.7.1, iPadOS 17.7.1, watchOS 11, and later versions as provided by Apple. 2. Implement strict web content filtering and restrict access to untrusted or unknown websites, especially those hosting iframe content. 3. Educate users about the risks of interacting with suspicious web content and phishing attempts that could trigger this vulnerability. 4. Use browser security extensions or enterprise policies to limit iframe usage or sandbox attributes where feasible. 5. Monitor network traffic and browser logs for unusual iframe behavior or attempts to exploit custom URL schemes. 6. Employ endpoint detection and response (EDR) solutions capable of detecting anomalous browser activity related to iframe sandbox violations. 7. For web developers, review and harden iframe sandbox policies and avoid reliance solely on browser sandboxing for critical security controls. 8. Coordinate with Apple support channels for any additional guidance or mitigation tools specific to this vulnerability.