CVE-2020-9993 in iOS
Summary
by MITRE • 12/09/2020
The issue was addressed with improved UI handling. This issue is fixed in watchOS 7.0, Safari 14.0, iOS 14.0 and iPadOS 14.0. Visiting a malicious website may lead to address bar spoofing.
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Analysis
by VulDB Data Team • 12/15/2020
The vulnerability identified as CVE-2020-9993 represents a significant user interface security flaw that enables malicious actors to manipulate the address bar display in web browsers. This issue specifically affects Apple's ecosystem including watchOS 7.0, Safari 14.0, iOS 14.0, and iPadOS 14.0. The flaw stems from inadequate validation and handling of user interface elements, particularly the address bar component that users rely upon for verifying website authenticity and security. The vulnerability falls under the category of UI redressing or UI spoofing attacks as defined by CWE-611, where attackers can deceive users into believing they are visiting a legitimate website when in fact they are interacting with a malicious page. This type of attack directly targets user trust and security expectations by manipulating visual elements that are fundamental to web browsing security.
The technical implementation of this vulnerability allows attackers to craft malicious websites that can display false address bar information, making it appear as though users are visiting a trusted domain when they are actually interacting with a deceptive site. The flaw likely resides in how the browser's rendering engine processes and displays URL information within the address bar, potentially through improper handling of HTML elements or JavaScript that controls UI display components. When users visit these malicious sites, the browser's UI handling mechanisms fail to properly validate or sanitize the address bar content, allowing attackers to inject deceptive elements that can fool even security-conscious users. This vulnerability represents a direct violation of the principle of least privilege in user interface security, where the browser should maintain strict control over how URL information is displayed to prevent user deception.
The operational impact of CVE-2020-9993 extends beyond simple phishing attacks to potentially enable more sophisticated social engineering campaigns that can bypass traditional security measures. Users may unknowingly enter sensitive information on malicious sites that appear legitimate due to the spoofed address bar, making this vulnerability particularly dangerous for financial transactions, credential entry, and other security-sensitive activities. The attack vector requires users to actively visit malicious websites, but the ease of implementation and the high trust users place in address bar information makes this a significant risk. This vulnerability directly relates to ATT&CK technique T1566 which involves social engineering through deceptive UI elements, and specifically targets the user trust model that browsers maintain for website authentication. The impact is particularly severe because users often rely on address bar information as their primary means of verifying website legitimacy, making the spoofing effect highly effective for credential theft and data exfiltration attacks.
The remediation for CVE-2020-9993 was implemented through improved UI handling mechanisms in Apple's operating system updates, specifically addressing how address bar information is processed and displayed within the Safari browser and related operating systems. The fix likely involved stricter validation of URL components, enhanced sandboxing of UI rendering processes, and improved separation between legitimate browser UI elements and potentially malicious content. Organizations should ensure immediate deployment of the affected system updates to protect against this vulnerability, as the window of exploitation exists between the vulnerability disclosure and patch deployment. System administrators should also consider implementing additional security measures such as web filtering solutions and user education programs to mitigate risks while waiting for patch deployment. The vulnerability serves as a reminder of the importance of UI security in modern browsers and the need for comprehensive security testing that includes user interface components, as these elements often serve as the primary interface for user security decisions.