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MEDIUM6.5

GHSA-2xhg-w2g5-w95x

CSV Injection in symfony/serializer

Quick fix

GHSA-2xhg-w2g5-w95x — symfony/serializer: upgrade to the fixed version with the command below.

composer require symfony/serializer:^5.3.12

Details

Description -----------

CSV Injection, also known as Formula Injection, occurs when websites embed untrusted input inside CSV files. When a spreadsheet program opens a CSV, any cell starting with `=` is interpreted by the software as a formula and could be abused by an attacker.

In Symfony 4.1, we've added the opt-in `csv_escape_formulas` option in `CsvEncoder`, to prefix all cells starting by `=`, `+`, `-` or `@` by a tab `\t`.

Since then, OWASP added 2 chars in that list: - Tab (0x09) - Carriage return (0x0D)

This makes our previous prefix char (Tab `\t`) part of the vulnerable characters, and [OWASP suggests](https://owasp.org/www-community/attacks/CSV_Injection) using the single quote `'` for prefixing the value.

Resolution ----------

Symfony now follows the OWASP recommendations and use the single quote `'` to prefix formulas and adds the prefix to cells starting by `\t`, `\r` as well as `=`, `+`, `-` and `@`.

The patch for this issue is available [here](https://github.com/symfony/symfony/commit/3da6f2d45e7536ccb2a26f52fbaf340917e208a8) for branch 4.4.

Credits -------

We would like to thank Jake Barwell for reporting the issue and Jérémy Derussé for fixing the issue.

Are you affected?

Enter the version of the package you're using.

Affected packages

Packagist/symfony/serializer
Introduced in: 5.0.0Fixed in: 5.3.12
Fixcomposer require symfony/serializer:^5.3.12
Packagist/symfony/serializer
Introduced in: 4.1.0Fixed in: 4.4.35
Fixcomposer require symfony/serializer:^4.4.35
Packagist/symfony/symfony
Introduced in: 4.1.0Fixed in: 4.4.35
Fixcomposer require symfony/symfony:^4.4.35
Packagist/symfony/symfony
Introduced in: 5.0.0Fixed in: 5.3.12
Fixcomposer require symfony/symfony:^5.3.12

References