CVE-2017-2504 in Safari
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.3.2 is affected. Safari before 10.1.1 is affected. tvOS before 10.2.1 is affected. The issue involves the "WebKit" component. It allows remote attackers to conduct Universal XSS (UXSS) attacks via a crafted web site that improperly interacts with WebKit Editor commands.
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Analysis
by VulDB Data Team • 08/24/2024
The vulnerability identified as CVE-2017-2504 represents a critical security flaw within Apple's WebKit rendering engine that affected multiple Apple operating systems including iOS versions prior to 10.3.2 Safari versions before 10.1.1 and tvOS versions before 10.2.1. This vulnerability resides in the WebKit component which serves as the foundation for web content rendering across Apple's ecosystem and is particularly concerning due to its classification as a Universal Cross-Site Scripting (UXSS) flaw. The technical nature of this vulnerability stems from improper handling of WebKit Editor commands when processing crafted web content that allows malicious actors to bypass existing security mechanisms and execute arbitrary code within the context of the victim's browser session.
The core technical flaw manifests through the WebKit Editor's insufficient validation of user-supplied input when processing specific web content that triggers editor commands. Attackers can craft malicious websites that exploit this weakness by leveraging WebKit's editor functionality to inject and execute malicious scripts across different browser contexts. This vulnerability is particularly dangerous because it operates as a Universal XSS attack which means that the malicious code can potentially bypass traditional security measures such as content security policies and cross-origin restrictions that typically protect against standard cross-site scripting attacks. The flaw essentially allows attackers to execute scripts in the context of any domain that the browser has visited, creating a comprehensive attack surface that extends beyond typical XSS limitations.
The operational impact of CVE-2017-2504 is substantial as it enables remote attackers to conduct sophisticated attacks without requiring local system access or user interaction beyond visiting a malicious website. This vulnerability particularly affects users of Apple's mobile and television platforms where Safari serves as the primary web browser, potentially allowing attackers to steal session cookies, perform unauthorized actions on behalf of users, or even gain access to sensitive personal information. The attack vector requires no special privileges or complex exploitation techniques, making it particularly dangerous for widespread use. The vulnerability's classification under CWE-79 indicates that it represents a weakness in the web application's input handling where the application fails to properly validate or sanitize user-provided data before incorporating it into dynamic content, which is a fundamental security principle that directly contradicts the secure coding practices recommended by OWASP and other industry standards.
Mitigation strategies for CVE-2017-2504 primarily involve immediate system updates to the affected Apple operating systems as recommended by Apple's security advisories. Users should ensure their iOS Safari tvOS and related systems are updated to versions 10.3.2 10.1.1 and 10.2.1 respectively to address the vulnerability. Additionally, security professionals should implement network-level protections such as web application firewalls and content filtering systems to detect and block known malicious patterns. The vulnerability's characteristics align with ATT&CK technique T1211 which involves exploiting browser vulnerabilities to execute malicious code, making it essential for organizations to monitor for indicators of compromise related to this specific attack pattern. Organizations should also consider implementing additional browser hardening measures including disabling unnecessary browser features and implementing strict content security policies to minimize the potential impact of any successful exploitation attempts.