CVE-2020-1096 in Edge
Summary
by MITRE
A remote code execution vulnerability exists when Microsoft Edge PDF Reader improperly handles objects in memory, aka 'Microsoft Edge PDF Remote Code Execution Vulnerability'.
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Analysis
by VulDB Data Team • 10/17/2020
The vulnerability identified as CVE-2020-1096 represents a critical remote code execution flaw within Microsoft Edge's PDF Reader component that has significant implications for enterprise security and user safety. This vulnerability specifically affects the handling of objects in memory during PDF document processing, creating a pathway for malicious actors to execute arbitrary code on affected systems. The flaw exists within the browser's PDF rendering engine, which is responsible for interpreting and displaying PDF documents directly within the Edge browser interface without requiring external applications. Attackers can exploit this weakness by crafting malicious PDF files that, when opened in Microsoft Edge, trigger the vulnerable code path in the PDF Reader module. The vulnerability's remote nature means that adversaries can deliver malicious payloads through web-based attacks, email attachments, or compromised websites without requiring local system access or user interaction beyond opening the PDF document.
The technical implementation of this vulnerability stems from improper memory handling within the PDF Reader's object processing routines, which falls under the CWE-129 weakness category of "Improper Validation of Array Index" and potentially CWE-787 "Out-of-bounds Write." The flaw manifests when the PDF Reader attempts to process malformed or specially crafted PDF objects that exceed expected memory boundaries or violate expected data structures. This memory handling issue creates opportunities for buffer overflow conditions or other memory corruption scenarios that can be leveraged by attackers to inject and execute malicious code. The vulnerability is particularly dangerous because it operates within the browser's trusted execution environment, where the PDF Reader component has sufficient privileges to manipulate system resources. The attack vector typically involves delivering a malicious PDF file through phishing campaigns or compromised web content, where users inadvertently trigger the vulnerable code path upon document opening.
The operational impact of CVE-2020-1096 extends beyond simple exploitation, as it can enable full system compromise and persistence mechanisms within enterprise environments. When successfully exploited, this vulnerability allows attackers to execute code with the privileges of the Edge process, potentially leading to complete system compromise or lateral movement within network environments. The vulnerability affects Microsoft Edge versions prior to the security updates released in October 2020, making it a significant concern for organizations that have not yet applied the necessary patches. Security researchers have documented various attack scenarios where this vulnerability has been used to establish persistent backdoors, exfiltrate sensitive data, or deploy additional malware payloads. The vulnerability's presence in the PDF Reader component means that any organization relying on Edge for document viewing or business-critical applications may be at risk, particularly in environments where users frequently open PDF documents from external sources or untrusted websites.
Mitigation strategies for CVE-2020-1096 require immediate action from organizations to protect their systems from exploitation attempts. The primary recommended approach involves applying the Microsoft security updates released in October 2020, which include patches specifically addressing the memory handling issues within the PDF Reader component. Organizations should also implement network-level protections such as web application firewalls and content filtering solutions that can detect and block malicious PDF content before it reaches user systems. Additional defensive measures include disabling PDF rendering within browsers where possible, implementing strict email filtering policies to prevent malicious PDF attachments, and conducting regular security awareness training to educate users about the risks of opening untrusted PDF documents. Security teams should also monitor for exploitation attempts through network traffic analysis and endpoint detection systems, as the vulnerability may manifest through specific network patterns or behavioral indicators that can be detected before full compromise occurs. The ATT&CK framework categorizes this vulnerability under T1203 "Exploitation for Client Execution" and T1059 "Command and Scripting Interpreter" as attackers leverage the vulnerability to execute malicious code and establish persistent access to target systems.