CVE-2021-41270
MEDIUM6.5EPSS 0.87%CSV Injection in symfony/serializer
Description
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.
Affected packages (4)
- Bitnami/symfony>= 4.1.0, < 4.4.35, >= 5.0.0, < 5.3.12
- Debian/symfonyfrom 0, < 4.4.19+dfsg-2+deb11u1
- Packagist/symfony/serializer>= 5.0.0, < 5.3.12
- Packagist/symfony/symfony>= 4.1.0, < 4.4.35
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
References (16)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2021-41270
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-41270
- PATCHhttps://github.com/symfony/symfony
- WEBhttps://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/serializer/CVE-2021-41270.yaml
- WEBhttps://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2021-41270.yaml
- WEBhttps://github.com/symfony/symfony/commit/3da6f2d45e7536ccb2a26f52fbaf340917e208a8
- WEBhttps://github.com/symfony/symfony/pull/44243
- WEBhttps://github.com/symfony/symfony/releases/tag/v5.3.12
- WEBhttps://github.com/symfony/symfony/security/advisories/GHSA-2xhg-w2g5-w95x
- WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3BPT4SF6SIXFMZARDWED5T32J7JEH3EP
- WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3BPT4SF6SIXFMZARDWED5T32J7JEH3EP/
- WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QSREFD2TJT5LWKM6S4MD3W26NQQ5WJUP
- WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QSREFD2TJT5LWKM6S4MD3W26NQQ5WJUP/
- WEBhttps://lists.fedoraproject.org/archives/list/[email protected]/message/3BPT4SF6SIXFMZARDWED5T32J7JEH3EP
- WEBhttps://lists.fedoraproject.org/archives/list/[email protected]/message/QSREFD2TJT5LWKM6S4MD3W26NQQ5WJUP
- WEBhttps://symfony.com/cve-2021-41270