CVE-2021-21288 : Security Advisory and Response

CarrierWave is an open-source RubyGem that allows easy file uploads from Ruby applications. Versions before 1.3.2 and 2.1.1 are susceptible to SSRF attacks, enabling threat actors to access internal IP addresses and Intranet structure details. The vulnerability has been patched in versions 1.3.2 and 2.1.1.

Understanding CVE-2021-21288

This CVE discloses a Server-Side Request Forgery (SSRF) vulnerability in CarrierWave, potentially leading to unauthorized access to sensitive network information.

What is CVE-2021-21288?

CVE-2021-21288 highlights an SSRF flaw in CarrierWave, allowing attackers to manipulate the download feature to extract internal network data.

The Impact of CVE-2021-21288

The vulnerability exposes platforms to data exfiltration attacks by malicious actors aiming to compromise network confidentiality.

Technical Details of CVE-2021-21288

The vulnerability has a CVSS base score of 4.3, denoting a medium severity flaw with low attack complexity and requirements. It affects CarrierWave versions < 1.3.2 and >= 2.0.0, < 2.1.1.

Vulnerability Description

CarrierWave's SSRF vulnerability in pre-1.3.2 and 2.1.1 versions allows unauthorized network accesses, posing a security risk to sensitive data.

Affected Systems and Versions

Versions < 1.3.2 and >= 2.0.0, < 2.1.1 of CarrierWave are susceptible to this SSRF flaw, impacting systems that use these versions.

Exploitation Mechanism

Threat actors can exploit the SSRF vulnerability in CarrierWave to elicit DNS entries or IP addresses intended for internal network usage.

Mitigation and Prevention

To address CVE-2021-21288, users should take immediate action, followed by a strategic security approach for long-term protection.

Immediate Steps to Take

Update CarrierWave to versions 1.3.2 or 2.1.1 to mitigate the SSRF risk. Verify network logs for any unusual activities indicating a potential exploit.

Long-Term Security Practices

Implement network segmentation, access controls, and regular security audits to fortify defenses against SSRF and other vulnerabilities.

Patching and Updates

Stay informed about security patches and updates for CarrierWave to ensure ongoing protection against emerging threats.