Analysis
- max time kernel
149s - max time network
150s - platform
windows11-21h2_x64 - resource
win11-20260130-en - resource tags
- submitted
15/04/2026, 16:10
General
- Target usbfallback.exe
- Size 3.1MB
- Sample260415-tmpehsdt2k
- SHA256 6029a278d4c0525bd9aaa754fcfb9c3c6b652249a26ff4592b42b9a9434d5d60
Malware Config
Extracted
-
quasar
-
1.4.1
-
HACKED
-
86.135.2.35:7752
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034caf8b-590c-452b-8e34-665ddd4b3cb4
-
encryption_key
E0127CB029C9D3778D15D3948B41ECDC8B44FB03
-
install_name
usbfallback.exe
-
key_salt
bfeb1e56fbcd973bb219022430a57843003d5644d21e62b9d4f180e7e6c33941
-
log_directory
Logs
-
reconnect_delay
3000
-
startup_key
Microsoft USB Fallback
-
subdirectory
Microsoft
Signatures
- Family: Quasar RAT
Quasar is an open source Remote Access Tool.
- Quasar payload 2 IoCs
- Executes dropped EXE 2 IoCs
- Looks up external IP address via web service 2 IoCs
Uses a legitimate IP lookup service to find the infected system's external IP.
- Scheduled Task/Job: Scheduled Task 1 TTPs 2 IoCs
Schtasks is often used by malware for persistence or to perform post-infection execution.
- 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\usbfallback.exe"C:\Users\Admin\AppData\Local\Temp\usbfallback.exe"1⤵
- Suspicious use of AdjustPrivilegeToken
- Suspicious use of WriteProcessMemory
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C:\Windows\SYSTEM32\schtasks.exe"schtasks" /create /tn "Microsoft USB Fallback" /sc ONLOGON /tr "C:\Users\Admin\AppData\Roaming\Microsoft\usbfallback.exe" /rl HIGHEST /f2⤵
- Scheduled Task/Job: Scheduled Task
-
-
C:\Users\Admin\AppData\Roaming\Microsoft\usbfallback.exe"C:\Users\Admin\AppData\Roaming\Microsoft\usbfallback.exe"2⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
- Suspicious use of WriteProcessMemory
-
C:\Windows\SYSTEM32\schtasks.exe"schtasks" /create /tn "Microsoft USB Fallback" /sc ONLOGON /tr "C:\Users\Admin\AppData\Roaming\Microsoft\usbfallback.exe" /rl HIGHEST /f3⤵
- Scheduled Task/Job: Scheduled Task
-
-
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C:\Users\Admin\AppData\Roaming\Microsoft\usbfallback.exeC:\Users\Admin\AppData\Roaming\Microsoft\usbfallback.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
Network
MITRE ATT&CK Enterprise v16
Replay Monitor
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Downloads
usbfallback.exe.log
usbfallback.exe
memory/1760-11-0x000000001B890000-0x000000001B8A0000-memory.dmp
memory/1760-15-0x000000001C420000-0x000000001C470000-memory.dmp
memory/1760-16-0x000000001C530000-0x000000001C5E2000-memory.dmp
memory/1760-17-0x00000000015F0000-0x00000000015FC000-memory.dmp
memory/1760-18-0x000000001B840000-0x000000001B852000-memory.dmp
memory/1760-19-0x000000001B890000-0x000000001B8A0000-memory.dmp
memory/2396-14-0x000000001BB80000-0x000000001BB92000-memory.dmp
memory/2396-13-0x0000000000F20000-0x0000000000F2C000-memory.dmp
memory/4900-1-0x000000001B450000-0x000000001B460000-memory.dmp
memory/4900-10-0x00000000029B0000-0x00000000029C2000-memory.dmp
memory/4900-9-0x0000000000F20000-0x0000000000F2C000-memory.dmp
memory/4900-0-0x00000000003E0000-0x0000000000704000-memory.dmp