buer | 6728db086194c2fa6a8e17e7b13bac1f5329b501e6f93b3587416895d387d343

General

Target

buer.exe
Size

111KB
MD5

f884618092b55e3edc48096757aab143
SHA1

0c0ad1301fc561699dba22cc779decc0df5570a1
SHA256

6728db086194c2fa6a8e17e7b13bac1f5329b501e6f93b3587416895d387d343
SHA512

195f4995907e34867d72778fb7e5857ea16e802376cf7ef17e2af3afa64e929bacfed4ed1b60d71a1ad8ea29e47c795c97ee7e41b6a02db59c9cc68fbb32e6ad

Score

10^/10

buer loader persistence

Malware Config

Extracted

Family

buer

C2

https://oopscll5.top/

https://1raidertr.top/

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\USER\S-1-5-21-910373003-3952921535-3480519689-1000\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell = "explorer.exe, \"C:\\ProgramData\\ErrorResponder\\errorResponder.exe\""	errorResponder.exe

Buer Loader 2 IoCs

Detects Buer loader in memory or disk.

resource	yara_rule
behavioral1/memory/1708-1-0x0000000040000000-0x000000004000B000-memory.dmp	buer
behavioral1/memory/1708-2-0x0000000040000000-0x000000004000B000-memory.dmp	buer

Executes dropped EXE 2 IoCs

pid	Process
1796	errorResponder.exe
1856	errorResponder.exe

Deletes itself 1 IoCs

pid	Process
1856	errorResponder.exe

Loads dropped DLL 3 IoCs

pid	Process
1416	buer.exe
1708	buer.exe
1796	errorResponder.exe

Suspicious use of SetThreadContext 2 IoCs

description	pid	Process	procid_target
PID 1416 set thread context of 1708	1416	buer.exe	26
PID 1796 set thread context of 1856	1796	errorResponder.exe	28

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

System Information Discovery
T1082

NSIS installer 8 IoCs

installer

resource	yara_rule
behavioral1/files/0x00030000000131c6-3.dat	nsis_installer_1
behavioral1/files/0x00030000000131c6-3.dat	nsis_installer_2
behavioral1/files/0x00030000000131c6-4.dat	nsis_installer_1
behavioral1/files/0x00030000000131c6-4.dat	nsis_installer_2
behavioral1/files/0x00030000000131c6-5.dat	nsis_installer_1
behavioral1/files/0x00030000000131c6-5.dat	nsis_installer_2
behavioral1/files/0x00030000000131c6-8.dat	nsis_installer_1
behavioral1/files/0x00030000000131c6-8.dat	nsis_installer_2

Suspicious behavior: MapViewOfSection 2 IoCs

pid	Process
1416	buer.exe
1796	errorResponder.exe

Suspicious use of WriteProcessMemory 18 IoCs

description	pid	Process	procid_target
PID 1416 wrote to memory of 1708	1416	buer.exe	26
PID 1416 wrote to memory of 1708	1416	buer.exe	26
PID 1416 wrote to memory of 1708	1416	buer.exe	26
PID 1416 wrote to memory of 1708	1416	buer.exe	26
PID 1416 wrote to memory of 1708	1416	buer.exe	26
PID 1708 wrote to memory of 1796	1708	buer.exe	27
PID 1708 wrote to memory of 1796	1708	buer.exe	27
PID 1708 wrote to memory of 1796	1708	buer.exe	27
PID 1708 wrote to memory of 1796	1708	buer.exe	27
PID 1796 wrote to memory of 1856	1796	errorResponder.exe	28
PID 1796 wrote to memory of 1856	1796	errorResponder.exe	28
PID 1796 wrote to memory of 1856	1796	errorResponder.exe	28
PID 1796 wrote to memory of 1856	1796	errorResponder.exe	28
PID 1796 wrote to memory of 1856	1796	errorResponder.exe	28
PID 1856 wrote to memory of 1760	1856	errorResponder.exe	29
PID 1856 wrote to memory of 1760	1856	errorResponder.exe	29
PID 1856 wrote to memory of 1760	1856	errorResponder.exe	29
PID 1856 wrote to memory of 1760	1856	errorResponder.exe	29

C:\Users\Admin\AppData\Local\Temp\buer.exe
"C:\Users\Admin\AppData\Local\Temp\buer.exe"
1⤵
- Loads dropped DLL
- Suspicious use of SetThreadContext
- Suspicious behavior: MapViewOfSection
- Suspicious use of WriteProcessMemory
PID:1416
- C:\Users\Admin\AppData\Local\Temp\buer.exe
  "C:\Users\Admin\AppData\Local\Temp\buer.exe"
  2⤵
  - Loads dropped DLL
  - Suspicious use of WriteProcessMemory
  PID:1708
- - C:\ProgramData\ErrorResponder\errorResponder.exe
    C:\ProgramData\ErrorResponder\errorResponder.exe "C:\Users\Admin\AppData\Local\Temp\buer.exe" ensgJJ
    3⤵
    - Executes dropped EXE
    - Loads dropped DLL
    - Suspicious use of SetThreadContext
    - Suspicious behavior: MapViewOfSection
    - Suspicious use of WriteProcessMemory
    PID:1796
  - - C:\ProgramData\ErrorResponder\errorResponder.exe
      C:\ProgramData\ErrorResponder\errorResponder.exe "C:\Users\Admin\AppData\Local\Temp\buer.exe" ensgJJ
      4⤵
      Modifies WinLogon for persistence
      Executes dropped EXE
      Deletes itself
      Suspicious use of WriteProcessMemory
      PID:1856
    - - C:\Windows\SysWOW64\secinit.exe
        
        C:\ProgramData\ErrorResponder\errorResponder.exe
        5⤵
        
        PID:1760

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

System Information Discovery

1

T1082

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

Replay Monitor

Loading Replay Monitor...

Downloads

memory/1708-1-0x0000000040000000-0x000000004000B000-memory.dmp

Filesize
44KB

Download
memory/1708-2-0x0000000040000000-0x000000004000B000-memory.dmp

Filesize
44KB

Download

Analysis

Sharing