CVE-2020-4809 in Edge
Summary
by MITRE • 09/24/2021
IBM Edge 4.2 allows web pages to be stored locally which can be read by another user on the system. IBM X-Force ID: 189633.
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Analysis
by VulDB Data Team • 10/01/2021
IBM Edge 4.2 contains a critical information disclosure vulnerability that arises from improper handling of locally stored web pages within the system's file structure. This vulnerability stems from the application's failure to implement proper access controls and file system permissions when storing web content locally on the device. The flaw allows an attacker with local system access to read web pages that were previously stored by other users, creating a cross-user data exposure scenario that violates fundamental security principles of user isolation and data protection.
The technical implementation of this vulnerability occurs when the IBM Edge 4.2 application stores web content in a shared or improperly secured local directory structure. When users browse the internet through the application, web pages including HTML documents, CSS files, JavaScript assets, and other resources are cached or stored locally for performance reasons. However, the application fails to enforce proper file system permissions that would restrict access to these stored resources based on user context, allowing unauthorized users to access the cached content of other system users. This represents a classic case of inadequate access control implementation where the system does not properly isolate user data at the file system level.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially expose sensitive user data, session information, or confidential web content that was intended to remain private to individual users. An attacker with local access to a system running IBM Edge 4.2 could leverage this vulnerability to gather intelligence about other users' browsing activities, potentially accessing personal information, business data, or other sensitive content that was cached locally. This vulnerability directly impacts the confidentiality aspect of the CIA triad and can be categorized under CWE-284 (Improper Access Control) and CWE-532 (Information Exposure Through Log Data) in the CWE database.
This vulnerability aligns with several tactics and techniques outlined in the MITRE ATT&CK framework, particularly those related to privilege escalation and credential access. The flaw enables a local attacker to perform unauthorized data access against other user accounts without requiring elevated privileges or complex exploitation techniques. The vulnerability can be exploited as part of a broader attack chain where an initial foothold is established through local access, followed by information gathering and lateral movement based on the exposure of cached web content. Organizations should consider this vulnerability when assessing their local privilege escalation attack vectors and user isolation controls within their security posture.
Mitigation strategies for this vulnerability should include implementing proper file system access controls that enforce user-specific permissions on locally stored web content, regular security audits of local storage directories, and application-level enforcement of access controls that prevent cross-user data access. System administrators should ensure that all locally cached web content is stored in directories with appropriate permissions that restrict access to the specific user context that generated the content. Additionally, implementing monitoring controls to detect unauthorized access attempts to cached web content can help identify potential exploitation attempts. Organizations should also consider updating to patched versions of IBM Edge 4.2 where appropriate, as this vulnerability represents a fundamental flaw in the application's data handling and access control implementation that requires both immediate remediation and long-term architectural improvements to prevent similar issues in other components of the system.