buer | 94ba896b284005a58298806bba47f725cdcaa1816b3c79226639cb145bf16886

General

Target

Docum_nt_Pr_view.exe
Size

709KB
MD5

96878fda61a76395aafa16a6150b0fe1
SHA1

3509a916a873351ab23bc671cce5ca9aa3299e62
SHA256

94ba896b284005a58298806bba47f725cdcaa1816b3c79226639cb145bf16886
SHA512

4e98e7b32441d270496b35c13e16ca0fedfca10e8baf8cb92a0a54fc803fb2bbfbc3417fe22467c195655821167d068a0ccde3310b45c75cada677ccea638234

Score

10^/10

buer loader persistence

Malware Config

Extracted

Family

buer

C2

https://165.22.76.41/

Signatures

Buer
Buer is a new modular loader first seen in August 2019.
loader buer

Modifies WinLogon for persistence 2 TTPs 1 IoCs

persistence

Winlogon Helper DLL

T1004

Modify Registry

T1112

description	ioc	Process
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell = "explorer.exe, \"C:\\ProgramData\\d30ec0e82aaf410c54c1\\gennt.exe\""	gennt.exe

Buer Loader 3 IoCs

Detects Buer loader in memory or disk.

resource	yara_rule
behavioral2/memory/520-0-0x0000000000700000-0x000000000070F000-memory.dmp	buer
behavioral2/memory/520-1-0x0000000040000000-0x000000004000C000-memory.dmp	buer
behavioral2/memory/4024-5-0x00000000001F0000-0x00000000001FF000-memory.dmp	buer

Executes dropped EXE 1 IoCs

pid	Process
4024	gennt.exe

Deletes itself 1 IoCs

pid	Process
4024	gennt.exe

Enumerates connected drives 3 TTPs 24 IoCs

Attempts to read the root path of hard drives other than the default C: drive.

Query Registry

T1012

Peripheral Device Discovery

T1120

System Information Discovery

T1082

description	ioc	Process
File opened (read-only)	\??\Z:	gennt.exe
File opened (read-only)	\??\E:	gennt.exe
File opened (read-only)	\??\F:	gennt.exe
File opened (read-only)	\??\G:	gennt.exe
File opened (read-only)	\??\L:	gennt.exe
File opened (read-only)	\??\P:	gennt.exe
File opened (read-only)	\??\Q:	gennt.exe
File opened (read-only)	\??\U:	gennt.exe
File opened (read-only)	\??\A:	gennt.exe
File opened (read-only)	\??\I:	gennt.exe
File opened (read-only)	\??\J:	gennt.exe
File opened (read-only)	\??\B:	gennt.exe
File opened (read-only)	\??\O:	gennt.exe
File opened (read-only)	\??\S:	gennt.exe
File opened (read-only)	\??\T:	gennt.exe
File opened (read-only)	\??\V:	gennt.exe
File opened (read-only)	\??\Y:	gennt.exe
File opened (read-only)	\??\H:	gennt.exe
File opened (read-only)	\??\K:	gennt.exe
File opened (read-only)	\??\M:	gennt.exe
File opened (read-only)	\??\N:	gennt.exe
File opened (read-only)	\??\R:	gennt.exe
File opened (read-only)	\??\W:	gennt.exe
File opened (read-only)	\??\X:	gennt.exe

Suspicious behavior: EnumeratesProcesses 3 IoCs

pid	Process
3640	powershell.exe
3640	powershell.exe
3640	powershell.exe

Suspicious use of AdjustPrivilegeToken 1 IoCs

description	pid	Process
Token: SeDebugPrivilege	3640	powershell.exe

Suspicious use of WriteProcessMemory 6 IoCs

description	pid	Process	procid_target
PID 520 wrote to memory of 4024	520	Docum_nt_Pr_view.exe	76
PID 520 wrote to memory of 4024	520	Docum_nt_Pr_view.exe	76
PID 520 wrote to memory of 4024	520	Docum_nt_Pr_view.exe	76
PID 4024 wrote to memory of 3640	4024	gennt.exe	78
PID 4024 wrote to memory of 3640	4024	gennt.exe	78
PID 4024 wrote to memory of 3640	4024	gennt.exe	78

C:\Users\Admin\AppData\Local\Temp\Docum_nt_Pr_view.exe
"C:\Users\Admin\AppData\Local\Temp\Docum_nt_Pr_view.exe"
1⤵
- Suspicious use of WriteProcessMemory
PID:520
- C:\ProgramData\d30ec0e82aaf410c54c1\gennt.exe
  C:\ProgramData\d30ec0e82aaf410c54c1\gennt.exe "C:\Users\Admin\AppData\Local\Temp\Docum_nt_Pr_view.exe" ensgJJ
  2⤵
  - Modifies WinLogon for persistence
  - Executes dropped EXE
  - Deletes itself
  - Enumerates connected drives
  - Suspicious use of WriteProcessMemory
  PID:4024
- - C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe
    powershell.exe -Command "& {Add-MpPreference -ExclusionPath C:\ProgramData\d30ec0e82aaf410c54c1}"
    3⤵
    - Suspicious behavior: EnumeratesProcesses
    - Suspicious use of AdjustPrivilegeToken
    PID:3640

Network

MITRE ATT&CK Enterprise v6

Initial Access

Execution

Persistence

Winlogon Helper DLL

1

T1004

Privilege Escalation

Defense Evasion

Modify Registry

1

T1112

Credential Access

Discovery

Peripheral Device Discovery

Query Registry

System Information Discovery

1

T1082

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

Replay Monitor

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Downloads

memory/520-1-0x0000000040000000-0x000000004000C000-memory.dmp

Filesize
48KB

Download
memory/520-0-0x0000000000700000-0x000000000070F000-memory.dmp

Filesize
60KB

Download
memory/3640-16-0x0000000008830000-0x0000000008831000-memory.dmp

Filesize
4KB

Download
memory/3640-14-0x0000000008460000-0x0000000008461000-memory.dmp

Filesize
4KB

Download
memory/3640-8-0x0000000073D50000-0x000000007443E000-memory.dmp

Filesize
6.9MB

Download
memory/3640-9-0x0000000007310000-0x0000000007311000-memory.dmp

Filesize
4KB

Download
memory/3640-10-0x0000000007AF0000-0x0000000007AF1000-memory.dmp

Filesize
4KB

Download
memory/3640-11-0x0000000007820000-0x0000000007821000-memory.dmp

Filesize
4KB

Download
memory/3640-12-0x0000000008190000-0x0000000008191000-memory.dmp

Filesize
4KB

Download
memory/3640-13-0x00000000083F0000-0x00000000083F1000-memory.dmp

Filesize
4KB

Download
memory/3640-31-0x0000000009D30000-0x0000000009D31000-memory.dmp

Filesize
4KB

Download
memory/3640-15-0x0000000008160000-0x0000000008161000-memory.dmp

Filesize
4KB

Download
memory/3640-29-0x0000000009D40000-0x0000000009D41000-memory.dmp

Filesize
4KB

Download
memory/3640-17-0x0000000008A90000-0x0000000008A91000-memory.dmp

Filesize
4KB

Download
memory/3640-19-0x0000000009880000-0x00000000098B3000-memory.dmp

Filesize
204KB

Download
memory/3640-26-0x0000000009860000-0x0000000009861000-memory.dmp

Filesize
4KB

Download
memory/3640-27-0x0000000009BD0000-0x0000000009BD1000-memory.dmp

Filesize
4KB

Download
memory/3640-28-0x0000000009DA0000-0x0000000009DA1000-memory.dmp

Filesize
4KB

Download
memory/4024-5-0x00000000001F0000-0x00000000001FF000-memory.dmp

Filesize
60KB

Download

Analysis

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