CVE-2020-19947 in Markdown Edit
Summary
by MITRE • 03/16/2023
Cross Site Scripting vulnerability found in Markdown Edit allows a remote attacker to execute arbitrary code via the edit parameter of the webpage.
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Analysis
by VulDB Data Team • 04/11/2023
The vulnerability identified as CVE-2020-19947 represents a critical cross site scripting flaw within the Markdown Edit web application that exposes organizations to significant remote code execution risks. This vulnerability specifically affects the edit parameter handling within the web interface, creating an attack vector that allows malicious actors to inject and execute arbitrary code on affected systems. The flaw resides in the application's insufficient input validation and output encoding mechanisms, which fail to properly sanitize user-supplied data before rendering it within the web page context. This weakness enables attackers to craft malicious payloads that can bypass security controls and establish persistent access to vulnerable environments.
The technical implementation of this vulnerability stems from improper handling of user input within the Markdown Edit application's parameter processing logic. When the edit parameter receives unvalidated input, the application fails to implement adequate sanitization measures that would normally prevent malicious scripts from being executed in the browser context. This represents a classic case of insufficient input validation and output encoding, which aligns with CWE-79 - Improper Neutralization of Input During Web Page Generation. The vulnerability operates by allowing an attacker to inject malicious javascript code through the edit parameter, which then executes in the context of other users who view the affected page. This creates a persistent threat where compromised users become unwitting carriers of the malicious payload, potentially leading to broader system compromise.
The operational impact of CVE-2020-19947 extends beyond simple script execution to encompass potential data breaches, system compromise, and unauthorized access to sensitive information. Attackers can leverage this vulnerability to steal session cookies, redirect users to malicious sites, perform actions on behalf of authenticated users, and potentially escalate privileges within the affected system. The remote nature of the attack means that exploitation can occur from anywhere on the internet without requiring physical access to the target network, making this vulnerability particularly dangerous in environments where the application is publicly accessible. Organizations using Markdown Edit applications may experience unauthorized data access, modification of content, and potential complete system compromise if proper mitigations are not implemented.
Mitigation strategies for CVE-2020-19947 should focus on implementing robust input validation and output encoding controls within the application's parameter handling logic. Organizations must ensure that all user-supplied input undergoes strict sanitization before being processed or rendered within the web interface. This includes implementing proper content security policies, using parameterized queries where applicable, and ensuring that all output is properly escaped to prevent script execution. The solution aligns with ATT&CK technique T1203 - Exploitation for Client Execution, which emphasizes the importance of preventing malicious code execution through proper input validation. Regular security updates and patches should be applied to the Markdown Edit application to address the root cause of the vulnerability, while network monitoring should be enhanced to detect potential exploitation attempts. Additionally, implementing web application firewalls and intrusion detection systems can provide additional layers of protection against this type of attack vector.