CVE-2021-41270 : What You Need to Know

Symfony versions 4.1.0 before 4.4.35 and versions 5.0.0 before 5.3.12 are vulnerable to CSV injection, also known as formula injection. Read on to understand the impact and how to mitigate this issue effectively.

Understanding CVE-2021-41270

CSV Injection vulnerability in Symfony

What is CVE-2021-41270?

Symfony, a PHP framework for web and console applications, is vulnerable to CSV injection, allowing attackers to abuse the CSV formatting by injecting formulas within cells.

The Impact of CVE-2021-41270

CVSS Base Score: 6.5 (Medium)
Attack Vector: Network
Confidentiality Impact: High
Integrity Impact: None
Privileges Required: Low
Vector String: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Technical Details of CVE-2021-41270

Symphony vulnerability details

Vulnerability Description

Symphony's

CsvEncoder

allowed prefixing specific characters with a tab, making the system vulnerable to CSV injection.

Affected Systems and Versions

Products: Symfony
Affected Versions: >= 4.1.0, < 4.4.35 and >= 5.0.0, < 5.3.12

Exploitation Mechanism

Attackers can inject malicious formulas into cells potentially leading to code execution when processed.

Mitigation and Prevention

How to address the CVE-2021-41270 vulnerability

Immediate Steps to Take

Upgrade Symfony to versions 4.4.35 or 5.3.12 that introduced the CSV injection fix.
Review and sanitize CSV inputs to prevent malicious injections.

Long-Term Security Practices

Implement input validation mechanisms to detect and block malicious CSV inputs.
Regularly monitor security advisories and update Symfony to the latest versions.

Patching and Updates

Follow OWASP recommendations to safely handle CSV data.