Analysis
- user interaction
yes - max time kernel
1049s - max time network
1042s - platform
windows11-21h2_x64 - resource
win11-20260130-en - resource tags
- submitted
05/03/2026, 07:55
General
- Target Client-built.exe
- Size 899KB
- Sample260305-jsas7set3l
- SHA256 5998e0267bb2a4ed86a7981857fdea8982d2d8be09c1aaeffdc43f5dd05fa2fd
Malware Config
Extracted
-
quasar
-
1.5.1
-
dsc.gg/un1x
-
tcp3.tunnel4.com:40271
-
b793e3e0-a400-4de4-b8c2-5204267d2218
-
encryption_key
CB770BFF9A5C5A8F92F2B4E2FE12549CF3DC3381
-
install_name
OfficeUpdater.exe
-
key_salt
5a23f8394640cb9e40658446a04c0bbae82dc93d0470e1b2a406a90fd2520382
-
log_directory
Logs
-
reconnect_delay
2997
-
startup_key
Microsoft Updater
-
subdirectory
MicrosoftOffice
Signatures
- Quasar RAT
Quasar is an open source Remote Access Tool.
- Quasar family
- Quasar payload 2 IoCs
- Executes dropped EXE 2 IoCs
- Scheduled Task/Job: Scheduled Task 1 TTPs 2 IoCs
Schtasks is often used by malware for persistence or to perform post-infection execution.
- Suspicious behavior: AddClipboardFormatListener 1 IoCs
- Suspicious use of AdjustPrivilegeToken 3 IoCs
- Suspicious use of WriteProcessMemory 3 IoCs
- Uses Task Scheduler COM API 1 TTPs
The Task Scheduler COM API can be used to schedule applications to run on boot or at set times.
Processes
-
C:\Users\Admin\AppData\Local\Temp\Client-built.exe"C:\Users\Admin\AppData\Local\Temp\Client-built.exe"1⤵
- Suspicious use of AdjustPrivilegeToken
- Suspicious use of WriteProcessMemory
-
C:\Windows\SYSTEM32\schtasks.exe"schtasks" /create /tn "Microsoft Updater" /sc ONLOGON /tr "C:\Users\Admin\AppData\Roaming\MicrosoftOffice\OfficeUpdater.exe" /rl HIGHEST /f2⤵
- Scheduled Task/Job: Scheduled Task
-
-
C:\Users\Admin\AppData\Roaming\MicrosoftOffice\OfficeUpdater.exe"C:\Users\Admin\AppData\Roaming\MicrosoftOffice\OfficeUpdater.exe"2⤵
- Executes dropped EXE
- Suspicious behavior: AddClipboardFormatListener
- Suspicious use of AdjustPrivilegeToken
- Suspicious use of WriteProcessMemory
-
C:\Windows\SYSTEM32\schtasks.exe"schtasks" /create /tn "Microsoft Updater" /sc ONLOGON /tr "C:\Users\Admin\AppData\Roaming\MicrosoftOffice\OfficeUpdater.exe" /rl HIGHEST /f3⤵
- Scheduled Task/Job: Scheduled Task
-
-
-
C:\Users\Admin\AppData\Roaming\MicrosoftOffice\OfficeUpdater.exeC:\Users\Admin\AppData\Roaming\MicrosoftOffice\OfficeUpdater.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
Network
MITRE ATT&CK Enterprise v16
Replay Monitor
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Downloads
OfficeUpdater.exe
memory/440-15-0x00000214C3EA0000-0x00000214C3EAC000-memory.dmp
memory/440-16-0x00000214DE180000-0x00000214DE192000-memory.dmp
memory/2780-11-0x000002516AB70000-0x000002516AB80000-memory.dmp
memory/2780-13-0x000002516B3C0000-0x000002516B410000-memory.dmp
memory/2780-17-0x000002516B4D0000-0x000002516B582000-memory.dmp
memory/2780-18-0x000002516B370000-0x000002516B3BE000-memory.dmp
memory/2780-19-0x0000025152320000-0x000002515232C000-memory.dmp
memory/2780-21-0x000002516AB70000-0x000002516AB80000-memory.dmp
memory/2780-20-0x000002516AB40000-0x000002516AB52000-memory.dmp
memory/4652-9-0x000001CF31B90000-0x000001CF31BA2000-memory.dmp
memory/4652-8-0x000001CF31A10000-0x000001CF31A1C000-memory.dmp
memory/4652-0-0x000001CF31510000-0x000001CF315F6000-memory.dmp
memory/4652-2-0x000001CF31AE0000-0x000001CF31AFA000-memory.dmp
memory/4652-1-0x000001CF31A20000-0x000001CF31A30000-memory.dmp