ghsa-2xhg-w2g5-w95x
Vulnerability from github
Published
2021-11-24 21:01
Modified
2024-02-05 11:14
Severity ?
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Summary
CSV Injection in symfony/serializer
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 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 for branch 4.4.

Credits

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

Show details on source website

To clipboard 

{
   affected: [
      {
         package: {
            ecosystem: "Packagist",
            name: "symfony/serializer",
         },
         ranges: [
            {
               events: [
                  {
                     introduced: "5.0.0",
                  },
                  {
                     fixed: "5.3.12",
                  },
               ],
               type: "ECOSYSTEM",
            },
         ],
      },
      {
         package: {
            ecosystem: "Packagist",
            name: "symfony/serializer",
         },
         ranges: [
            {
               events: [
                  {
                     introduced: "4.1.0",
                  },
                  {
                     fixed: "4.4.35",
                  },
               ],
               type: "ECOSYSTEM",
            },
         ],
      },
      {
         package: {
            ecosystem: "Packagist",
            name: "symfony/symfony",
         },
         ranges: [
            {
               events: [
                  {
                     introduced: "4.1.0",
                  },
                  {
                     fixed: "4.4.35",
                  },
               ],
               type: "ECOSYSTEM",
            },
         ],
      },
      {
         package: {
            ecosystem: "Packagist",
            name: "symfony/symfony",
         },
         ranges: [
            {
               events: [
                  {
                     introduced: "5.0.0",
                  },
                  {
                     fixed: "5.3.12",
                  },
               ],
               type: "ECOSYSTEM",
            },
         ],
      },
   ],
   aliases: [
      "CVE-2021-41270",
   ],
   database_specific: {
      cwe_ids: [
         "CWE-1236",
      ],
      github_reviewed: true,
      github_reviewed_at: "2021-11-24T20:04:02Z",
      nvd_published_at: "2021-11-24T19:15:00Z",
      severity: "MODERATE",
   },
   details: "Description\n-----------\n\nCSV 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.\n\nIn 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`. \n\nSince then, OWASP added 2 chars in that list: \n- Tab (0x09)\n- Carriage return (0x0D)\n\nThis 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.\n\nResolution\n----------\n\nSymfony 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 `@`.\n\nThe patch for this issue is available [here](https://github.com/symfony/symfony/commit/3da6f2d45e7536ccb2a26f52fbaf340917e208a8) for branch 4.4.\n\nCredits\n-------\n\nWe would like to thank Jake Barwell for reporting the issue and Jérémy Derussé for fixing the issue.\n",
   id: "GHSA-2xhg-w2g5-w95x",
   modified: "2024-02-05T11:14:05Z",
   published: "2021-11-24T21:01:23Z",
   references: [
      {
         type: "WEB",
         url: "https://github.com/symfony/symfony/security/advisories/GHSA-2xhg-w2g5-w95x",
      },
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2021-41270",
      },
      {
         type: "WEB",
         url: "https://github.com/symfony/symfony/pull/44243",
      },
      {
         type: "WEB",
         url: "https://github.com/symfony/symfony/commit/3da6f2d45e7536ccb2a26f52fbaf340917e208a8",
      },
      {
         type: "WEB",
         url: "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/serializer/CVE-2021-41270.yaml",
      },
      {
         type: "WEB",
         url: "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2021-41270.yaml",
      },
      {
         type: "PACKAGE",
         url: "https://github.com/symfony/symfony",
      },
      {
         type: "WEB",
         url: "https://github.com/symfony/symfony/releases/tag/v5.3.12",
      },
      {
         type: "WEB",
         url: "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3BPT4SF6SIXFMZARDWED5T32J7JEH3EP",
      },
      {
         type: "WEB",
         url: "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QSREFD2TJT5LWKM6S4MD3W26NQQ5WJUP",
      },
      {
         type: "WEB",
         url: "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3BPT4SF6SIXFMZARDWED5T32J7JEH3EP",
      },
      {
         type: "WEB",
         url: "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QSREFD2TJT5LWKM6S4MD3W26NQQ5WJUP",
      },
      {
         type: "WEB",
         url: "https://symfony.com/cve-2021-41270",
      },
   ],
   schema_version: "1.4.0",
   severity: [
      {
         score: "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
         type: "CVSS_V3",
      },
   ],
   summary: "CSV Injection in symfony/serializer",
}


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