CVE-2020-1433 in Edge
Summary
by MITRE
An information disclosure vulnerability exists when Microsoft Edge PDF Reader improperly handles objects in memory, aka 'Microsoft Edge PDF Information Disclosure Vulnerability'.
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Analysis
by VulDB Data Team • 10/29/2020
The CVE-2020-1433 vulnerability represents a critical information disclosure flaw within Microsoft Edge's PDF Reader component that stems from improper memory object handling during PDF document processing. This vulnerability specifically affects the way Microsoft Edge parses and manages PDF objects in memory, creating potential pathways for attackers to extract sensitive information from the browser's memory space. The flaw exists at the intersection of memory management and document parsing, where malformed or specially crafted PDF elements can trigger unexpected behavior in the Edge rendering engine. Such vulnerabilities are particularly dangerous because they can be exploited through web-based attacks without requiring user interaction beyond visiting a malicious website, making them highly prevalent in phishing campaigns and drive-by download scenarios.
The technical implementation of this vulnerability involves memory corruption patterns that occur when the PDF Reader component encounters improperly structured PDF objects during parsing operations. When Microsoft Edge processes PDF documents, it creates internal memory representations of various PDF elements including fonts, images, and metadata structures. The vulnerability manifests when these memory objects are not properly validated or sanitized, allowing for information leakage through memory read operations that should be restricted. This type of flaw typically aligns with CWE-200, which covers "Information Exposure," and may also relate to CWE-125, "Out-of-bounds Read," depending on the specific memory access patterns. The vulnerability operates at the application layer and can be categorized under ATT&CK technique T1059.001 for command and scripting interpreter, though primarily as an information gathering mechanism rather than execution.
The operational impact of CVE-2020-1433 extends beyond simple data exposure, as the information disclosure can potentially include sensitive data from other applications running in the same memory space, session tokens, or even partial memory contents that could aid in more sophisticated attacks. Attackers could leverage this vulnerability to extract browser session information, cached data, or other sensitive memory contents that might reveal user credentials, personal information, or system configurations. The vulnerability affects Microsoft Edge versions that include the PDF Reader functionality, typically those running on Windows 10 operating systems and potentially older Windows versions that support Edge's PDF handling capabilities. This makes it particularly dangerous in enterprise environments where Edge is the default browser and users frequently access untrusted websites or documents.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected Microsoft Edge versions, as Microsoft released security updates specifically addressing this memory handling issue. Organizations should implement browser hardening measures including disabling PDF Reader functionality in Edge when not required, implementing strict web content filtering, and monitoring for suspicious PDF-related network traffic. Security teams should also consider deploying web application firewalls that can detect and block malformed PDF content, as well as implementing memory protection mechanisms such as DEP (Data Execution Prevention) and ASLR (Address Space Layout Randomization) to reduce the effectiveness of potential exploitation attempts. Additionally, user education regarding the risks of opening untrusted PDF documents and maintaining current security patches remains crucial in preventing successful exploitation of this information disclosure vulnerability.