CWE-1236

Improper Neutralization of Formula Elements in a CSV File

Medium

Description

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.

Potential Impact

How to Fix

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).

Implementation

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

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.

Detection Methods

Related Weaknesses

References

View on MITRE CWE Database →

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