Understanding VEC Attacks: Vendor Email Compromise and How to Defend Against Them

By /

Listen to this Post

Featured Image

Introduction

Vendor Email Compromise (VEC) is a sophisticated cyberattack where threat actors impersonate trusted vendors to deceive organizations into fraudulent transactions, malware distribution, or credential theft. Unlike traditional Business Email Compromise (BEC), VEC specifically exploits trusted vendor relationships, making detection more challenging. This article explores VEC attacks, their mechanisms, and actionable defenses.

Learning Objectives

  • Understand how VEC attacks differ from BEC and phishing.
  • Learn detection techniques for fraudulent vendor emails.
  • Implement technical safeguards to mitigate VEC risks.

1. Detecting Suspicious Vendor Emails with DMARC/DKIM

Command (Linux/MTA Configuration):

cat /etc/opendkim/keys/example.com/default.private

What It Does:

This command displays the private DKIM key used to sign outgoing emails, ensuring authenticity.

Step-by-Step Guide:

1. Install OpenDKIM:

sudo apt-get install opendkim opendkim-tools

2. Generate DKIM Keys:

sudo opendkim-genkey -b 2048 -d example.com -D /etc/opendkim/keys/example.com -s default -v

3. Configure DNS: Add the generated `default.txt` public key to your DNS TXT records.
4. Verify Emails: Use tools like MXToolbox to validate DKIM/DMARC alignment.

2. Analyzing Email Headers for Fraud

Command (Windows PowerShell):

Get-MessageTrackingLog -Sender "[email protected]" -EventId "RECEIVE" | Format-List

What It Does:

Retrieves email header metadata to trace sender IP, routing, and authentication results.

Step-by-Step Guide:

1. Open Exchange Management Shell.

  1. Run the above command to inspect headers for mismatched domains or spoofed addresses.

3. Check for `Authentication-Results: fail` in headers.

3. Blocking Malicious Domains with SPF

DNS Record Example:

v=spf1 include:_spf.example.com ~all

What It Does:

SPF records define authorized email servers for a domain.

Step-by-Step Guide:

  1. Access your DNS management console (e.g., Cloudflare, Route53).
  2. Add the SPF record above, replacing `_spf.example.com` with your vendor’s SPF include.

3. Test with:

dig TXT example.com
  1. Automating Vendor Email Verification with API Security

Python Script (API Check):

import requests 
response = requests.get("https://api.abnormalsecurity.com/v1/[email protected]") 
print(response.json())

What It Does:

Queries threat intelligence APIs to validate vendor emails.

Step-by-Step Guide:

  1. Sign up for an API key (e.g., Abnormal Security, Proofpoint).

2. Run the script to flag suspicious vendors.

5. Training Teams to Spot VEC Attacks

Phishing Simulation Command (Linux):

sudo gophish

What It Does:

Launches GoPhish, an open-source phishing simulation toolkit.

Step-by-Step Guide:

1. Install GoPhish:

wget https://github.com/gophish/gophish/releases/download/v0.11.0/gophish-v0.11.0-linux-64bit.zip

2. Simulate VEC attacks to train employees.

What Undercode Say

  • Key Takeaway 1: VEC attacks exploit trust, requiring layered defenses (DMARC, DKIM, SPF).
  • Key Takeaway 2: Automation (APIs, header analysis) reduces reliance on human vigilance.

Analysis:

VEC attacks are rising due to weak vendor email authentication. Organizations must adopt technical controls (SPF/DKIM) and continuous training. Future AI-driven email filters may help, but human skepticism remains critical.

Prediction

By 2025, VEC attacks will account for 30% of BEC losses as attackers refine impersonation tactics. Proactive adoption of AI-based email security (e.g., Abnormal Security) and zero-trust vendor onboarding will become industry standards.

IT/Security Reporter URL:

Reported By: Mthomasson Threat – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

Join Our Cyber World:

💬 Whatsapp | 💬 Telegram

Related Posts: