Sanitize your CSV to avoid CSV Injection.

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Explanation

The following CSV will execute the Formula =1+1 with the Microsoft Excel or LibreOffice Calc opening.

First Name,Second Name,Phone Number,Birth Year
Bob,Doe,123123123,1994
Alice,Cooper,321321321,1993
PoC,CSVi,=1+1,@test

To avoid this injection, is enough to add a blankspace before the = sign.

The output CSV will be:

First Name,Second Name,Phone Number,Birth Year
Bob,Doe,123123123,1994
Alice,Cooper,321321321,1993
PoC,CSVi, =1+1, @test

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Usage

Usage:

go run GOCiS.go -in original.csv -out sanitized.csv

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About CSV Injection

Accorging to OWASP: CSV Injection:

CSV Injection, also known as Formula Injection, occurs when websites embed untrusted input inside CSV files.

When a spreadsheet program such as Microsoft Excel or LibreOffice Calc is used to open a CSV, any cells starting with = will be interpreted by the software as a formula. Maliciously crafted formulas can be used for three key attacks:

• Hijacking the user's computer by exploiting vulnerabilities in the spreadsheet software, such as CVE-2014-3524.
• Hijacking the user's computer by exploiting the user's tendency to ignore security warnings in spreadsheets that they downloaded from their own website.
• Exfiltrating contents from the spreadsheet, or other open spreadsheets.

This attack is difficult to mitigate, and explicitly disallowed from quite a few bug bounty programs. To remediate it, ensure that no cells begin with any of the following characters:

• Equals to (=)
• Plus (+)
• Minus (-)
• At (@)