CVE-2017-0241 in Edge
Summary
by MITRE
An elevation of privilege vulnerability exists when Microsoft Edge renders a domain-less page in the URL, which could allow Microsoft Edge to perform actions in the context of the Intranet Zone and access functionality that is not typically available to the browser when browsing in the context of the Internet Zone, aka "Microsoft Edge Elevation of Privilege Vulnerability." This CVE ID is unique from CVE-2017-0233.
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Analysis
by VulDB Data Team • 12/22/2020
The vulnerability identified as CVE-2017-0241 represents a critical elevation of privilege flaw in Microsoft Edge browser that stems from improper handling of domain-less pages within URL structures. This security weakness specifically manifests when the browser encounters web content that lacks explicit domain information in its URL formatting, creating an unexpected behavioral context that allows for privilege escalation. The flaw exploits the browser's zone handling mechanisms, where normally restricted functionality in the Internet Zone becomes accessible when processing certain malformed or domain-less page references.
This vulnerability operates through a zone boundary crossing mechanism that violates Microsoft's security model for web browser isolation. When Microsoft Edge processes a domain-less page, the browser incorrectly assigns the page to the Intranet Zone context rather than maintaining the expected Internet Zone restrictions. This misclassification allows the malicious page to access intranet resources, local file system operations, and other privileged functions that should remain restricted to the Internet Zone. The vulnerability specifically affects how the browser determines trust boundaries and zone assignments for pages that lack explicit domain information in their URL structure, creating a pathway for unauthorized access to normally protected resources.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential data exfiltration and system compromise scenarios. An attacker could craft malicious web pages that, when loaded in Microsoft Edge, would gain access to local network resources, file system operations, and potentially execute arbitrary code with elevated privileges. The vulnerability's exploitation requires user interaction through visiting a malicious website, but once triggered, it could enable attackers to access corporate networks, internal systems, and sensitive data that would normally be protected by the browser's security model. This represents a significant risk in enterprise environments where Edge browser is commonly used for internet browsing and internal network access.
The technical implementation of this vulnerability aligns with CWE-264, which addresses permissions, privileges, and access controls in software systems. The flaw demonstrates a failure in proper privilege management and zone isolation within Microsoft Edge's security architecture. From an attack perspective, this vulnerability maps to several ATT&CK techniques including T1068 for exploit for privilege escalation and T1059 for command and scripting interpreter. The vulnerability's exploitation pathway involves manipulating browser zone assignments through URL structure manipulation, which falls under the category of browser-based attack vectors that bypass traditional network security controls.
Mitigation strategies for CVE-2017-0241 should prioritize immediate patch application through Microsoft's security updates, as this vulnerability was addressed through official security releases. Organizations should also implement network-based protections such as web application firewalls and content filtering systems that can detect and block suspicious URL patterns. Browser hardening measures including disabling unnecessary features, implementing strict content security policies, and configuring zone-based security settings can provide additional defense layers. Security monitoring should focus on detecting unusual browser behavior patterns and unauthorized access attempts to internal network resources, particularly when users access external websites that may contain malicious content designed to exploit this privilege escalation vulnerability.