guloader | b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2

General

Target
b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe
Size 664KB
Sample260205-tptr1sdt5f
SHA256 b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2
MD5 074bb3720d90a19975ecdca1b1fd7fd7
SHA1 184c42a3a4b222dea1579b8b0ae7b79887cfe91e
SHA512 2319995c3c6d873c00e76072a290ce83f88e8627a5594f60b3cd5d1c941b26f4eeaca2179af6fd01df94cc410fe170baab685dd608a2b360424858b2db9a0043
SSDEEP 12288:lBNUqpxqIuNp9rnVXbUttpwWGRA+POobvoE5j4RcWaKIyOiy3N:FBpkJnnNIz6RtWGoG421ey3N
TLSH
T1F7E4236132B28D72F557123554A25FAA1E5BCC12142871632342BD9BECFA3B2DD3E387
MD5 SHA1 SHA512 SSDEEP TLSH

Score

10^/10

discovery downloader guloader

Malware Config

Signatures

Guloader family
guloader
Guloader,Cloudeye
A shellcode based downloader first seen in 2020.
downloader guloader

Loads dropped DLL 2 IoCs

pid	Process
4344	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe
4344	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe

Contacts third-party web service commonly abused for C2 1 TTPs 2 IoCs

Legitimate web (hosting) services can be abused by malware authors to host malware or C2s.

Web Service

T1102

flow	ioc
1	drive.google.com
2	drive.google.com

Suspicious use of NtSetInformationThreadHideFromDebugger 2 IoCs

pid	Process
4344	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe
4820	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe

Drops file in Windows directory 2 IoCs

description	ioc	Process
File created	C:\Windows\resources\refrnsangeren.lnk	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe
File opened for modification	C:\Windows\resources\refrnsangeren.lnk	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe

Enumerates physical storage devices 1 TTPs
Attempts to interact with connected storage/optical drive(s).

System Information Discovery
T1082

Program crash 1 IoCs

pid	pid_target	Process	procid_target
5680	4820	WerFault.exe	81

System Location Discovery: System Language Discovery 1 TTPs 2 IoCs

Attempt gather information about the system language of a victim in order to infer the geographical location of that host.

discovery

System Language Discovery

T1614.001

description	ioc	Process
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe

Suspicious behavior: MapViewOfSection 1 IoCs

pid	Process
4344	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe

Suspicious use of WriteProcessMemory 4 IoCs

description	pid	Process	procid_target
PID 4344 wrote to memory of 4816	4344	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe	80
PID 4344 wrote to memory of 4820	4344	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe	81
PID 4344 wrote to memory of 4820	4344	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe	81
PID 4820 wrote to memory of 3380	4820	b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe	82

C:\Users\Admin\AppData\Local\Temp\b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe
"C:\Users\Admin\AppData\Local\Temp\b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe"
1⤵
- Loads dropped DLL
- Suspicious use of NtSetInformationThreadHideFromDebugger
- Drops file in Windows directory
- System Location Discovery: System Language Discovery
- Suspicious behavior: MapViewOfSection
- Suspicious use of WriteProcessMemory
PID:4344
- C:\Users\Admin\AppData\Local\Temp\b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe
  "C:\Users\Admin\AppData\Local\Temp\b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe"
  2⤵
  PID:4816
- C:\Users\Admin\AppData\Local\Temp\b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe
  "C:\Users\Admin\AppData\Local\Temp\b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe"
  2⤵
  - Suspicious use of NtSetInformationThreadHideFromDebugger
  - System Location Discovery: System Language Discovery
  - Suspicious use of WriteProcessMemory
  PID:4820
- - C:\Users\Admin\AppData\Local\Temp\b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe
    "C:\Users\Admin\AppData\Local\Temp\b91b3e2c3e95e105fd0f5b910f936655b664bec6785a7d93e5c5a06168a663f2.exe"
    3⤵
    PID:3380
- - C:\Windows\SysWOW64\WerFault.exe
    C:\Windows\SysWOW64\WerFault.exe -u -p 4820 -s 1780
    3⤵
    - Program crash
    PID:5680

C:\Windows\SysWOW64\WerFault.exe
C:\Windows\SysWOW64\WerFault.exe -pss -s 204 -p 4820 -ip 4820
1⤵
PID:1320

Network

MITRE ATT&CK Enterprise v16

Reconnaissance

Resource Development

Initial Access

Execution

Persistence

Privilege Escalation

Defense Evasion

Credential Access

Discovery

System Information Discovery

1

T1082

System Location Discovery

1

T1614

System Language Discovery

1

T1614.001

Lateral Movement

Collection

Command and Control

Web Service

1

T1102

Exfiltration

Impact

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Downloads

System.dll

Path C:\Users\Admin\AppData\Local\Temp\nsr2F3A.tmp\System.dll
Size 11KB
SHA256 bd046e6497b304e4ea4ab102cab2b1f94ce09bde0eebba4c59942a732679e4eb
MD5 17ed1c86bd67e78ade4712be48a7d2bd
SHA1 1cc9fe86d6d6030b4dae45ecddce5907991c01a0
SHA512 0cbed521e7d6d1f85977b3f7d3ca7ac34e1b5495b69fd8c7bfa1a846baf53b0ecd06fe1ad02a3599082ffacaf8c71a3bb4e32dec05f8e24859d736b828092cd5
SSDEEP 192:eY24sihno00Wfl97nH6T2enXwWobpWBTU4VtHT7dmN35Ol+Sl:E8QIl975eXqlWBrz7YLOl+
TLSH
T1E3325C12135081F3E4918138C86B3A276B6A15029BF98E57DFD39546BE31BE3BD7D603
MD5 SHA1 SHA512 SSDEEP TLSH

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refrnsangeren.lnk

Path C:\Windows\Resources\refrnsangeren.lnk
Size 870B
SHA256 b0fd54a0ef4832bf63c455a48f8a4d980ea81c6fe749137ff5d726dc2bce207b
MD5 4167c50f57c6c8be4f0ad5d2f656b41e
SHA1 bcbae87aef1eeb939d494ebf2b73bef485e1bccd
SHA512 4e4740ba40dbac0ad224a2b7111fdbd2bcbd5cb6ddace91c14bb3978717eb9135c495ed61de6ffd5e05e1d34ddd1ad937de1353f129fd3e6a66fb146508fcfdb
TLSH
T13E1199144BE11214F3F3EF34A4F229065977BC01BE08CE0C1180428DA473A20E878F5F
MD5 SHA1 SHA512 TLSH

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memory/4344-329-0x0000000004930000-0x0000000006BA7000-memory.dmp

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memory/4344-330-0x0000000010004000-0x0000000010005000-memory.dmp

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memory/4344-331-0x0000000004930000-0x0000000006BA7000-memory.dmp

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memory/4820-343-0x00000000007E0000-0x0000000001AF7000-memory.dmp

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memory/4820-345-0x0000000001B00000-0x0000000003D77000-memory.dmp

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Analysis

Sharing

General

Malware Config

Signatures

Processes

Network

MITRE ATT&CK Enterprise v16

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Downloads