> Source: [sk183969](https://support.checkpoint.com/results/sk/sk183969)

# sk183969 - Data Loss Prevention blade blocks legitimate JavaScript traffic as C# source code

| Property | Value |
|----------|-------|
| Solution ID | sk183969 |
| Date Created | 2025-09-16 |
| Last Modified | 2026-03-10 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20 |
| OS | Gaia |
| Platform | 7000 |

## Symptoms

- * The Security Gateway incorrectly identifies websites containing JavaScript code as containing C# source code, and blocks access to them.

* Users cannot submit forms or load pages on affected websites due to false positive source code detection.

* Security Gateway logs show matches for keywords such as `typeof`, `if`, `return`, and `this.disabled` in JavaScript, which are incorrectly flagged as C# code.

## Cause

The Data Loss Prevention blade calculates a score for detected source code based on keyword matches as defined in `$FWDIR/conf/dlp_data_tbl.C.`. If the score is higher than the configured threshold, the traffic is blocked. JavaScript shares certain keywords with other programming languages, and legitimate JavaScript traffic may be incorrectly classified and blocked.

## Solution

This solution requires authentication. Please log in to view the full solution.

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