CVE-2015-3781 in Mac OS X
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Quick Look in Apple OS X before 10.10.5 allows remote attackers to inject arbitrary web script or HTML via a previously visited web site that is rendered during a Quick Look search.
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Analysis
by VulDB Data Team • 02/02/2025
The CVE-2015-3781 vulnerability represents a critical cross-site scripting flaw in Apple's Quick Look functionality affecting macOS versions prior to 10.10.5. This vulnerability exists within the way Quick Look processes and renders web content, creating a pathway for remote attackers to execute malicious scripts in the context of the user's browser. The flaw specifically manifests when users perform Quick Look searches on previously visited websites that contain maliciously crafted content, allowing attackers to inject arbitrary web scripts or HTML code directly into the Quick Look preview interface.
The technical exploitation of this vulnerability leverages the inherent trust users place in previously visited websites within the macOS ecosystem. When Quick Look renders search results or previews content from web pages, it fails to properly sanitize or escape user-supplied input from visited sites. This allows attackers to craft malicious web content that, when processed by Quick Look, executes in the context of the user's browser session. The vulnerability operates at the intersection of web rendering and desktop application functionality, where Quick Look's preview mechanism becomes an attack vector for cross-site scripting attacks.
From an operational perspective, this vulnerability poses significant risks to macOS users who frequently interact with web content through Quick Look functionality. The attack requires minimal user interaction beyond visiting a malicious website, making it particularly dangerous in phishing campaigns or targeted attacks. Security researchers have classified this as a server-side request forgery vulnerability that can be exploited through the client-side Quick Look component, with potential for privilege escalation depending on the user's system permissions. The vulnerability can be leveraged to steal session cookies, redirect users to malicious sites, or execute arbitrary code within the browser context.
This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications and client-side code processing. The attack pattern follows the typical exploitation methodology described in the MITRE ATT&CK framework under technique T1059.007 for script-based execution, where attackers leverage legitimate system functionality to execute malicious code. The vulnerability also demonstrates characteristics of T1566 related to spearphishing attacks, as users are typically lured to visit malicious websites that contain the payload. Organizations should note that this vulnerability affects the core operating system functionality and cannot be mitigated through traditional web application firewalls or browser security measures alone.
Mitigation strategies for CVE-2015-3781 primarily involve immediate system updates to macOS 10.10.5 or later versions where Apple has implemented proper input sanitization and content validation within Quick Look's web rendering components. System administrators should also consider implementing network-based controls to monitor and block access to known malicious domains, while users should exercise caution when visiting unfamiliar websites and avoid interacting with Quick Look previews of untrusted content. Additionally, organizations may want to disable Quick Look functionality in high-security environments or implement additional browser security controls to prevent exploitation of similar vulnerabilities in other components of the operating system.