CVE-2019-9844 : Exploit Details and Defense Strategies

Simple-markdown.js in Khan Academy before version 0.4.4 is vulnerable to cross-site scripting (XSS) attacks through data: or vbscript: URIs.

Understanding CVE-2019-9844

This CVE involves a security vulnerability in simple-markdown.js used in Khan Academy, allowing for XSS attacks.

What is CVE-2019-9844?

The version of simple-markdown.js used in Khan Academy, specifically before version 0.4.4, contains a vulnerability that allows cross-site scripting (XSS) attacks through the use of data: or vbscript: URIs.

The Impact of CVE-2019-9844

Attackers can exploit this vulnerability to execute malicious scripts on the victim's browser, potentially leading to data theft or unauthorized actions.

Technical Details of CVE-2019-9844

This section provides more technical insights into the CVE.

Vulnerability Description

The vulnerability in simple-markdown.js allows for XSS attacks via data: or vbscript: URIs.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: All versions before 0.4.4

Exploitation Mechanism

Attackers can craft malicious data: or vbscript: URIs to inject and execute scripts on vulnerable systems.

Mitigation and Prevention

Protecting systems from CVE-2019-9844 requires immediate actions and long-term security practices.

Immediate Steps to Take

Upgrade to version 0.4.4 or later of simple-markdown.js to mitigate the vulnerability.
Implement content security policies (CSP) to restrict script execution from unauthorized sources.

Long-Term Security Practices

Regularly update and patch software to address security flaws promptly.
Conduct security audits and code reviews to identify and fix vulnerabilities proactively.

Patching and Updates

Stay informed about security advisories and updates from Khan Academy and other relevant sources to apply patches promptly.