Protected File Transfers

🔐 Protected File Transfers – Doing It the Right Way

As penetration testers, we often deal with sensitive data:

• 🧑‍🤝‍🧑 User credentials

• 🗃️ Domain enumeration data

• 🛠️ Tools like NTDS.dit, LSASS, and scan logs

It’s critical that we encrypt anything we extract — both to protect clients and our own reputation. A simple oversight (like exfiltrating in plaintext) can lead to serious consequences. 🚨

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🧠 Pro Tip

If your goal is DLP testing, use dummy data that mimics sensitive content. Never transfer real PII, credentials, or trade secrets unless authorized.

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🪟 File Encryption on Windows

🔒 Invoke-AESEncryption.ps1

A lightweight and powerful PowerShell script that encrypts/decrypts:

• 🔐 Strings

• 📄 Files

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📥 Importing the Script

Import-Module .\Invoke-AESEncryption.ps1

After that, you can use it like any other cmdlet. ✅

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📦 Usage Examples

1️⃣ Encrypt a String (Base64 output)

Invoke-AESEncryption -Mode Encrypt -Key "p@ssw0rd" -Text "Secret Text"

2️⃣ Decrypt a String

Invoke-AESEncryption -Mode Decrypt -Key "p@ssw0rd" -Text "<Base64-String>"

3️⃣ Encrypt a File

Invoke-AESEncryption -Mode Encrypt -Key "p4ssw0rd" -Path .\scan-results.txt

🔄 Output: scan-results.txt.aes

4️⃣ Decrypt a File

Invoke-AESEncryption -Mode Decrypt -Key "p4ssw0rd" -Path .\scan-results.txt.aes

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🐧 File Encryption on Linux

🔒 OpenSSL Encryption

OpenSSL is built into most Linux distros and allows you to encrypt files with AES-256 💪

🔐 Encrypt a File

openssl enc -aes256 -iter 100000 -pbkdf2 -in /etc/passwd -out passwd.enc

You’ll be prompted to enter a password 🔑

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🔓 Decrypt a File

openssl enc -d -aes256 -iter 100000 -pbkdf2 -in passwd.enc -out passwd

Same password required to decrypt.

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🛡️ Security Best Practices

• ✅ Use strong, unique passwords for each engagement

• ❌ Avoid using the same encryption key across clients

• ⚠️ If encryption is not an option, do not exfil highly sensitive files

• 💬 Communicate encryption methods clearly in your report

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🧳 Transfer Tips

Once encrypted, you can safely transfer files using:

• ✅ HTTPS

• ✅ SFTP

• ✅ SCP/SSH

• ✅ Encrypted tunnels

❌ Avoid: Plain HTTP, SMB, FTP unless you're testing insecure protocols

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