Common Weakness Enumeration

CWE-1236

Allowed

Improper Neutralization of Formula Elements in a CSV File

Abstraction: Base · Status: Incomplete

API response cwe.mitre.org

The product saves user-provided information into a Comma-Separated Value (CSV) file, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as a command when the file is opened by a spreadsheet product.

401 vulnerabilities reference this CWE, most recent first.

GHSA-XXJ6-2W57-FCHV

Vulnerability from github – Published: 2022-05-24 19:19 – Updated: 2022-05-24 19:19
VLAI
Details

In Mahara before 20.04.5, 20.10.3, 21.04.2, and 21.10.0, exported CSV files could contain characters that a spreadsheet program could interpret as a command, leading to execution of a malicious string locally on a device, aka CSV injection.

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{
  "affected": [],
  "aliases": [
    "CVE-2021-40848"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1236"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2021-11-03T11:15:00Z",
    "severity": "HIGH"
  },
  "details": "In Mahara before 20.04.5, 20.10.3, 21.04.2, and 21.10.0, exported CSV files could contain characters that a spreadsheet program could interpret as a command, leading to execution of a malicious string locally on a device, aka CSV injection.",
  "id": "GHSA-xxj6-2w57-fchv",
  "modified": "2022-05-24T19:19:35Z",
  "published": "2022-05-24T19:19:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-40848"
    },
    {
      "type": "WEB",
      "url": "https://bugs.launchpad.net/mahara/+bug/1930471"
    },
    {
      "type": "WEB",
      "url": "https://mahara.org/interaction/forum/topic.php?id=8950"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}
Mitigation
Implementation

When generating CSV output, ensure that formula-sensitive metacharacters are effectively escaped or removed from all data before storage in the resultant CSV. Risky characters include '=' (equal), '+' (plus), '-' (minus), and '@' (at).

Mitigation
Implementation

If a field starts with a formula character, prepend it with a ' (single apostrophe), which prevents Excel from executing the formula.

Mitigation
Architecture and Design

Certain implementations of spreadsheet software might disallow formulas from executing if the file is untrusted, or if the file is not authored by the current user.

No CAPEC attack patterns related to this CWE.

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