Malware Analysis Report

2024-11-13 18:30

Sample ID 241107-arhyratlfj
Target skuld.exe
SHA256 031f10cbf44a49a9b60f16d7226a790338989e8721bc69bf6d4cd3df9977aed4
Tags
skuld persistence
score
10/10

Table of Contents

Analysis Overview

MITRE ATT&CK

Enterprise Matrix V15

Analysis: static1

Detonation Overview

Signatures

Analysis: behavioral1

Detonation Overview

Command Line

Signatures

Processes

Network

Files

Analysis: behavioral2

Detonation Overview

Command Line

Signatures

Processes

Network

Files

Analysis Overview

score
10/10

SHA256

031f10cbf44a49a9b60f16d7226a790338989e8721bc69bf6d4cd3df9977aed4

Threat Level: Known bad

The file skuld.exe was found to be: Known bad.

Malicious Activity Summary

skuld persistence

Skuld family

Adds Run key to start application

Unsigned PE

Suspicious use of AdjustPrivilegeToken

Suspicious use of WriteProcessMemory

Views/modifies file attributes

MITRE ATT&CK

Analysis: static1

Detonation Overview

Reported

2024-11-07 00:26

Signatures

Skuld family

skuld

Unsigned PE

Description Indicator Process Target
N/A N/A N/A N/A

Analysis: behavioral1

Detonation Overview

Submitted

2024-11-07 00:26

Reported

2024-11-07 00:29

Platform

win10v2004-20241007-en

Max time kernel

91s

Max time network

145s

Command Line

"C:\Users\Admin\AppData\Local\Temp\skuld.exe"

Signatures

Adds Run key to start application

persistence
Description Indicator Process Target
Set value (str) \REGISTRY\USER\S-1-5-21-493223053-2004649691-1575712786-1000\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Realtek HD Audio Universal Service = "C:\\Users\\Admin\\AppData\\Roaming\\Microsoft\\Protect\\SecurityHealthSystray.exe" C:\Users\Admin\AppData\Local\Temp\skuld.exe N/A

Suspicious use of AdjustPrivilegeToken

Description Indicator Process Target
Token: SeDebugPrivilege N/A C:\Users\Admin\AppData\Local\Temp\skuld.exe N/A

Suspicious use of WriteProcessMemory

Description Indicator Process Target
PID 2700 wrote to memory of 2052 N/A C:\Users\Admin\AppData\Local\Temp\skuld.exe C:\Windows\system32\attrib.exe
PID 2700 wrote to memory of 2052 N/A C:\Users\Admin\AppData\Local\Temp\skuld.exe C:\Windows\system32\attrib.exe

Views/modifies file attributes

evasion
Description Indicator Process Target
N/A N/A C:\Windows\system32\attrib.exe N/A

Processes

C:\Users\Admin\AppData\Local\Temp\skuld.exe

"C:\Users\Admin\AppData\Local\Temp\skuld.exe"

C:\Windows\system32\attrib.exe

attrib +h +s C:\Users\Admin\AppData\Local\Temp\skuld.exe

Network

Country Destination Domain Proto
US 8.8.8.8:53 8.8.8.8.in-addr.arpa udp
US 8.8.8.8:53 13.86.106.20.in-addr.arpa udp
US 8.8.8.8:53 67.209.201.84.in-addr.arpa udp
US 8.8.8.8:53 73.31.126.40.in-addr.arpa udp
US 8.8.8.8:53 95.221.229.192.in-addr.arpa udp
US 8.8.8.8:53 241.150.49.20.in-addr.arpa udp
US 8.8.8.8:53 56.163.245.4.in-addr.arpa udp
US 8.8.8.8:53 206.23.85.13.in-addr.arpa udp
US 8.8.8.8:53 73.190.18.2.in-addr.arpa udp
US 8.8.8.8:53 79.190.18.2.in-addr.arpa udp
US 8.8.8.8:53 48.229.111.52.in-addr.arpa udp

Files

N/A

Analysis: behavioral2

Detonation Overview

Submitted

2024-11-07 00:26

Reported

2024-11-07 00:29

Platform

macos-20241106-en

Max time kernel

71s

Max time network

125s

Command Line

[sh -c sudo /bin/zsh -c "/Users/run/skuld.exe"]

Signatures

N/A

Processes

/bin/sh

[sh -c sudo /bin/zsh -c "/Users/run/skuld.exe"]

/bin/bash

[sh -c sudo /bin/zsh -c "/Users/run/skuld.exe"]

/usr/bin/sudo

[sudo /bin/zsh -c /Users/run/skuld.exe]

/bin/zsh

[/bin/zsh -c /Users/run/skuld.exe]

/Users/run/skuld.exe

[/Users/run/skuld.exe]

/usr/bin/bzip2

[/usr/bin/bzip2 -f /var/log/wifi.log.0]

Network

Country Destination Domain Proto
US 8.8.8.8:53 lb._dns-sd._udp.0.0.127.10.in-addr.arpa udp

Files

N/A