CVE-2020-4054 : Exploit Details and Defense Strategies

In Sanitize (RubyGem sanitize) greater than or equal to 3.0.0 and less than 5.2.1, a cross-site scripting vulnerability exists. This vulnerability allows attackers to inject arbitrary HTML code, potentially leading to XSS attacks.

Understanding CVE-2020-4054

Sanitize (RubyGem sanitize) versions >= 3.0.0, < 5.2.1 are affected by a cross-site scripting vulnerability.

What is CVE-2020-4054?

CVE-2020-4054 is a vulnerability in the Sanitize RubyGem that allows attackers to bypass HTML sanitization, leading to potential cross-site scripting attacks.

The Impact of CVE-2020-4054

The vulnerability has a CVSS base score of 7.3, indicating a high severity level. Attackers can exploit this issue to execute malicious scripts on the victim's browser, compromising confidentiality and integrity.

Technical Details of CVE-2020-4054

Sanitize (RubyGem sanitize) versions >= 3.0.0, < 5.2.1 are susceptible to a cross-site scripting vulnerability.

Vulnerability Description

When using Sanitize's "relaxed" config or a custom config allowing specific HTML elements, certain content in math or svg elements may not be sanitized correctly, potentially enabling attackers to inject malicious HTML.

Affected Systems and Versions

Product: Sanitize
Vendor: rgrove
Versions Affected: >= 3.0.0, < 5.2.1

Exploitation Mechanism

Attack Complexity: Low
Attack Vector: Network
Privileges Required: None
User Interaction: None
Scope: Unchanged
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Mitigation and Prevention

To address CVE-2020-4054, follow these steps:

Immediate Steps to Take

Update Sanitize to version 5.2.1 or later to mitigate the vulnerability.
Avoid using Sanitize's "relaxed" config or custom configs allowing potentially dangerous HTML elements.

Long-Term Security Practices

Regularly monitor for security advisories and updates related to Sanitize.
Implement input validation and output encoding to prevent XSS attacks.

Patching and Updates

Apply patches and updates provided by the vendor to ensure the security of the Sanitize library.