buer | cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9

General

Target

cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9.exe
Size

212KB
MD5

a4d06844d2cb6555d28d7160044df583
SHA1

bb25fc9c6bd3b6260d05b03fffbec75e679a81a9
SHA256

cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9
SHA512

bf3dd5469cfe2093505373a3ce7d322b6057fa367462b55be43b173febf1021d66b430f98ad78a497d2db93244b8a4f739136e5e680c9d2706383151c899cfc1

Score

10^/10

buer loader persistence

Malware Config

Extracted

Family

buer

C2

https://95.217.81.68/

http://95.217.81.68:8080/

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-1-5-21-1083475884-596052423-1669053738-1000\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell = "explorer.exe, \"C:\\ProgramData\\ErrorResponder\\errorResponder.exe\""	errorResponder.exe

Buer Loader 3 IoCs

Detects Buer loader in memory or disk.

loader

resource	yara_rule
behavioral1/memory/1260-56-0x0000000000020000-0x000000000002A000-memory.dmp	buer
behavioral1/memory/1260-57-0x0000000040000000-0x00000000404A8000-memory.dmp	buer
behavioral1/memory/2028-66-0x0000000040000000-0x00000000404A8000-memory.dmp	buer

Executes dropped EXE 1 IoCs

pid	Process
2028	errorResponder.exe

Deletes itself 1 IoCs

pid	Process
2028	errorResponder.exe

Loads dropped DLL 2 IoCs

pid	Process
1260	cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9.exe
1260	cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9.exe

Program crash 1 IoCs

pid	pid_target	Process	procid_target
1924	1200	WerFault.exe	29

Suspicious behavior: EnumeratesProcesses 1 IoCs

pid	Process
2028	errorResponder.exe

Suspicious use of WriteProcessMemory 19 IoCs

description	pid	Process	procid_target
PID 1260 wrote to memory of 2028	1260	cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9.exe	28
PID 1260 wrote to memory of 2028	1260	cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9.exe	28
PID 1260 wrote to memory of 2028	1260	cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9.exe	28
PID 1260 wrote to memory of 2028	1260	cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9.exe	28
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 2028 wrote to memory of 1200	2028	errorResponder.exe	29
PID 1200 wrote to memory of 1924	1200	secinit.exe	30
PID 1200 wrote to memory of 1924	1200	secinit.exe	30
PID 1200 wrote to memory of 1924	1200	secinit.exe	30
PID 1200 wrote to memory of 1924	1200	secinit.exe	30

C:\Users\Admin\AppData\Local\Temp\cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9.exe
"C:\Users\Admin\AppData\Local\Temp\cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9.exe"
1⤵
- Loads dropped DLL
- Suspicious use of WriteProcessMemory
PID:1260
- C:\ProgramData\ErrorResponder\errorResponder.exe
  C:\ProgramData\ErrorResponder\errorResponder.exe "C:\Users\Admin\AppData\Local\Temp\cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9.exe" ensgJJ
  2⤵
  - Modifies WinLogon for persistence
  - Executes dropped EXE
  - Deletes itself
  - Suspicious behavior: EnumeratesProcesses
  - Suspicious use of WriteProcessMemory
  PID:2028
- - C:\Windows\SysWOW64\secinit.exe
    C:\ProgramData\ErrorResponder\errorResponder.exe
    3⤵
    - Suspicious use of WriteProcessMemory
    PID:1200
  - - C:\Windows\SysWOW64\WerFault.exe
      C:\Windows\SysWOW64\WerFault.exe -u -p 1200 -s 136
      4⤵
      Program crash
      PID:1924

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

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

Replay Monitor

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Downloads

C:\ProgramData\ErrorResponder\errorResponder.exe

Filesize
212KB

MD5
a4d06844d2cb6555d28d7160044df583

SHA1
bb25fc9c6bd3b6260d05b03fffbec75e679a81a9

SHA256
cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9

SHA512
bf3dd5469cfe2093505373a3ce7d322b6057fa367462b55be43b173febf1021d66b430f98ad78a497d2db93244b8a4f739136e5e680c9d2706383151c899cfc1

Download Submit
C:\ProgramData\ErrorResponder\errorResponder.exe

Filesize
212KB

MD5
a4d06844d2cb6555d28d7160044df583

SHA1
bb25fc9c6bd3b6260d05b03fffbec75e679a81a9

SHA256
cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9

SHA512
bf3dd5469cfe2093505373a3ce7d322b6057fa367462b55be43b173febf1021d66b430f98ad78a497d2db93244b8a4f739136e5e680c9d2706383151c899cfc1

Download Submit
\ProgramData\ErrorResponder\errorResponder.exe

Filesize
212KB

MD5
a4d06844d2cb6555d28d7160044df583

SHA1
bb25fc9c6bd3b6260d05b03fffbec75e679a81a9

SHA256
cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9

SHA512
bf3dd5469cfe2093505373a3ce7d322b6057fa367462b55be43b173febf1021d66b430f98ad78a497d2db93244b8a4f739136e5e680c9d2706383151c899cfc1

Download Submit
\ProgramData\ErrorResponder\errorResponder.exe

Filesize
212KB

MD5
a4d06844d2cb6555d28d7160044df583

SHA1
bb25fc9c6bd3b6260d05b03fffbec75e679a81a9

SHA256
cfb4266735f9806e94537f71a1e289ce6db041484159c07be6a8d5b3ce12abf9

SHA512
bf3dd5469cfe2093505373a3ce7d322b6057fa367462b55be43b173febf1021d66b430f98ad78a497d2db93244b8a4f739136e5e680c9d2706383151c899cfc1

Download Submit
memory/1200-67-0x00000000002D0000-0x0000000000778000-memory.dmp

Filesize
4.7MB

Download
memory/1200-76-0x0000000000080000-0x0000000000081000-memory.dmp

Filesize
4KB

Download
memory/1200-80-0x00000000002D0000-0x0000000000778000-memory.dmp

Filesize
4.7MB

Download
memory/1200-68-0x00000000002D0000-0x0000000000778000-memory.dmp

Filesize
4.7MB

Download
memory/1200-70-0x00000000002D0000-0x0000000000778000-memory.dmp

Filesize
4.7MB

Download
memory/1200-72-0x00000000002D0000-0x0000000000778000-memory.dmp

Filesize
4.7MB

Download
memory/1200-74-0x00000000002D0000-0x0000000000778000-memory.dmp

Filesize
4.7MB

Download
memory/1260-54-0x0000000075501000-0x0000000075503000-memory.dmp

Filesize
8KB

Download
memory/1260-56-0x0000000000020000-0x000000000002A000-memory.dmp

Filesize
40KB

Download
memory/1260-55-0x00000000002CA000-0x00000000002D1000-memory.dmp

Filesize
28KB

Download
memory/1260-57-0x0000000040000000-0x00000000404A8000-memory.dmp

Filesize
4.7MB

Download
memory/2028-66-0x0000000040000000-0x00000000404A8000-memory.dmp

Filesize
4.7MB

Download
memory/2028-65-0x0000000000230000-0x0000000000330000-memory.dmp

Filesize
1024KB

Download

Analysis

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