CVE-2017-2393 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.3 is affected. The issue involves the "Safari Reader" component. It allows remote attackers to conduct Universal XSS (UXSS) attacks via a crafted web site.
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Analysis
by VulDB Data Team • 11/21/2022
The vulnerability identified as CVE-2017-2393 represents a critical security flaw in Apple's iOS operating system affecting versions prior to 10.3. This vulnerability specifically targets the Safari Reader component, which is a built-in feature designed to simplify web page reading by stripping away advertisements and clutter. The issue stems from insufficient input validation and sanitization within the Reader functionality, creating a pathway for malicious actors to exploit cross-site scripting vulnerabilities. The vulnerability is particularly concerning because it enables universal cross-site scripting attacks that can bypass traditional security mechanisms, allowing attackers to execute arbitrary code within the context of the user's browser session.
The technical implementation of this vulnerability occurs through the improper handling of HTML content within the Safari Reader component. When users navigate to malicious websites that have been crafted specifically to exploit this flaw, the Reader component fails to properly sanitize or escape user-provided content before rendering it. This allows attackers to inject malicious scripts that can execute with the privileges of the Safari Reader context, potentially enabling full exploitation of the user's browsing session. The vulnerability operates at the application layer and leverages the trust relationship between the user and the Safari browser, making it particularly dangerous in phishing and drive-by download scenarios.
The operational impact of CVE-2017-2393 extends beyond simple cross-site scripting, as it provides attackers with a persistent vector for executing more sophisticated attacks. Once an attacker successfully exploits this vulnerability, they can potentially access sensitive user data, hijack browser sessions, redirect users to malicious sites, or even install additional malware. The universal nature of the exploit means that it can affect any user who visits a compromised website while using Safari Reader, regardless of their security awareness or the presence of other security controls. This vulnerability particularly impacts enterprise environments where iOS devices are commonly used for business operations, as it could enable attackers to access corporate data through seemingly legitimate web browsing activities.
Organizations and individual users should immediately update to iOS 10.3 or later versions to remediate this vulnerability, as Apple released a security update specifically addressing this issue. Security professionals should implement additional monitoring for suspicious web traffic patterns and consider network-based controls to detect and block known malicious domains. The vulnerability aligns with CWE-79 which describes cross-site scripting flaws, and maps to attack techniques in the ATT&CK framework under T1211 for exploitation of web applications. Additional mitigations include disabling Safari Reader functionality where possible, implementing web application firewalls, and conducting regular security awareness training to help users identify potentially malicious websites. Organizations should also consider implementing browser hardening policies that restrict the execution of potentially malicious content within web browsers to reduce the attack surface.