CVE-2019-13144
📋 TL;DR
CVE-2019-13144 is a CSV injection vulnerability in myTinyTodo that allows attackers to inject malicious formulas into exported CSV files. When victims open these files in spreadsheet applications like Excel, the formulas execute, potentially leading to command execution or data theft. This affects all users of myTinyTodo versions 1.3.3 through 1.4.3.
💻 Affected Systems
- myTinyTodo
📦 What is this software?
Mytinytodo by Mytinytodo
⚠️ Risk & Real-World Impact
Worst Case
Attackers could execute arbitrary commands on victim systems when malicious CSV files are opened in vulnerable spreadsheet applications, potentially leading to full system compromise.
Likely Case
Attackers trick users into opening malicious CSV files that execute formulas to steal data, install malware, or perform other malicious actions on the victim's local system.
If Mitigated
If users open CSV files in plain text editors or with formula execution disabled, the impact is limited to data manipulation within the CSV file itself.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious CSV file) but the injection itself is straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.5
Vendor Advisory: https://www.mytinytodo.net/history.php
Restart Required: No
Instructions:
1. Download myTinyTodo version 1.5 or later from the official website. 2. Backup your current installation. 3. Replace the existing files with the new version. 4. Verify the update was successful.
🔧 Temporary Workarounds
Disable CSV Export
allRemove or disable CSV export functionality to prevent exploitation.
Remove CSV export feature from the application interface
Sanitize CSV Output
allAdd input validation to escape or remove formula characters from CSV exports.
Modify CSV generation code to prepend formula cells with single quote or escape special characters
🧯 If You Can't Patch
- Educate users to never open CSV files from untrusted sources in spreadsheet applications with formula execution enabled
- Configure spreadsheet applications to disable automatic formula execution when opening CSV files
🔍 How to Verify
Check if Vulnerable:
Check if your myTinyTodo version is between 1.3.3 and 1.4.3 inclusive, and test if CSV export allows injection of formulas starting with =, +, -, or @.Check Version:
Check the version.txt file in the myTinyTodo installation directory or view the version in the application interface.Verify Fix Applied:
After upgrading to version 1.5 or later, test CSV export to ensure formulas are properly escaped or prefixed with a single quote.📡 Detection & Monitoring
Log Indicators:
- Unusual CSV export requests, especially with suspicious payloads in parameters
Network Indicators:
- CSV file downloads containing formula characters at the beginning of cells
SIEM Query:
source="web_server" AND (uri="*export*" OR uri="*csv*") AND (payload="*=*" OR payload="*+*" OR payload="*-*" OR payload="*@*")