CVE-2015-3710 in Mac OS X
Summary
by MITRE
Mail in Apple iOS before 8.4 and OS X before 10.10.4 allows remote attackers to trigger a refresh operation, and consequently cause a visit to an arbitrary web site, via a crafted HTML e-mail message.
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Analysis
by VulDB Data Team • 11/25/2024
The vulnerability identified as CVE-2015-3710 represents a significant security flaw in Apple's Mail application affecting iOS versions prior to 8.4 and OS X versions prior to 10.10.4. This issue stems from improper handling of HTML content within email messages, creating a vector for malicious actors to exploit user trust and automate web navigation. The vulnerability specifically targets the automatic refresh functionality of the Mail application, which is designed to periodically update email content including embedded web resources.
The technical implementation of this flaw involves the manipulation of HTML email content to trigger unintended behavior in the Mail application's rendering engine. When a user opens a specially crafted email message containing malicious HTML code, the application's automatic refresh mechanism is activated in a way that causes the system to navigate to arbitrary web addresses without user interaction. This occurs because the Mail application fails to properly sanitize or validate HTML elements that could trigger navigation events, particularly those related to automatic refresh directives and URL redirection.
The operational impact of this vulnerability extends beyond simple phishing attacks, as it enables attackers to perform automated web navigation that could lead to various malicious outcomes including drive-by downloads, credential harvesting, or exploitation of additional vulnerabilities in the user's browser. The vulnerability operates through the principle of user deception where victims unknowingly trigger navigation to attacker-controlled websites simply by opening an email message, making it particularly dangerous in targeted attack scenarios. This behavior aligns with attack patterns documented in the attack mitigation framework where initial access is achieved through social engineering combined with automated exploitation techniques.
From a cybersecurity perspective, this vulnerability demonstrates the importance of proper input validation and the potential for seemingly benign application features to become attack vectors. The flaw relates to CWE-79 which describes Cross-Site Scripting vulnerabilities, though in this case the execution occurs within the email client rather than a web browser context. The vulnerability also maps to techniques described in the MITRE ATT&CK framework under Initial Access and Execution phases, specifically targeting the use of malicious email content to establish automated access paths.
Mitigation strategies for this vulnerability required immediate system updates to the affected Apple operating systems, as well as user education about the dangers of opening suspicious email content. Organizations needed to implement email filtering solutions that could detect and block HTML content with automatic refresh directives, while security teams should have monitored for indicators of compromise related to unauthorized web navigation patterns. The patch released by Apple addressed the underlying HTML parsing logic to ensure that automatic refresh operations could not be triggered by malformed email content, thereby preventing the unintended navigation behavior that enabled the exploitation.