buer | 75c82c63584c1f0abdbb0dbb6eb035e2e9f56110becb07faac43ff7ef5349709

General

Target

Invoice_8003346.xlsm

Score

10^/10

buer loader

Malware Config

Extracted

Family

buer

C2

verstudiosan.com

Signatures

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

Buer Loader 1 IoCs

Detects Buer loader in memory or disk.

resource	yara_rule
behavioral2/memory/3856-14-0x0000000040000000-0x0000000040009000-memory.dmp	buer

Executes dropped EXE 2 IoCs

pid	Process
2164	ServApi.exe
3856	ServApi.exe

Loads dropped DLL 1 IoCs

pid	Process
2164	ServApi.exe

Suspicious use of SetThreadContext 1 IoCs

description	pid	Process	procid_target
PID 2164 set thread context of 3856	2164	ServApi.exe	85

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

System Information Discovery
T1082

NSIS installer 6 IoCs

installer

resource	yara_rule
behavioral2/files/0x0003000000015641-9.dat	nsis_installer_1
behavioral2/files/0x0003000000015641-9.dat	nsis_installer_2
behavioral2/files/0x0003000000015641-10.dat	nsis_installer_1
behavioral2/files/0x0003000000015641-10.dat	nsis_installer_2
behavioral2/files/0x0003000000015641-13.dat	nsis_installer_1
behavioral2/files/0x0003000000015641-13.dat	nsis_installer_2

Checks processor information in registry 2 TTPs 3 IoCs

Processor information is often read in order to detect sandboxing environments.

Query Registry

T1012

System Information Discovery

T1082

description	ioc	Process
Key opened	\REGISTRY\MACHINE\Hardware\Description\System\CentralProcessor\0	EXCEL.EXE
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0\~MHz	EXCEL.EXE
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0\ProcessorNameString	EXCEL.EXE

Enumerates system info in registry 2 TTPs 3 IoCs

Query Registry

T1012

System Information Discovery

T1082

description	ioc	Process
Key opened	\REGISTRY\MACHINE\Hardware\Description\System\BIOS	EXCEL.EXE
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\BIOS\SystemFamily	EXCEL.EXE
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\BIOS\SystemSKU	EXCEL.EXE

Suspicious behavior: AddClipboardFormatListener 1 IoCs

pid	Process
1056	EXCEL.EXE

Suspicious behavior: MapViewOfSection 1 IoCs

pid	Process
2164	ServApi.exe

Suspicious use of SetWindowsHookEx 12 IoCs

pid	Process
1056	EXCEL.EXE
1056	EXCEL.EXE
1056	EXCEL.EXE
1056	EXCEL.EXE
1056	EXCEL.EXE
1056	EXCEL.EXE
1056	EXCEL.EXE
1056	EXCEL.EXE
1056	EXCEL.EXE
1056	EXCEL.EXE
1056	EXCEL.EXE
1056	EXCEL.EXE

Suspicious use of WriteProcessMemory 7 IoCs

description	pid	Process	procid_target
PID 1056 wrote to memory of 2164	1056	EXCEL.EXE	81
PID 1056 wrote to memory of 2164	1056	EXCEL.EXE	81
PID 1056 wrote to memory of 2164	1056	EXCEL.EXE	81
PID 2164 wrote to memory of 3856	2164	ServApi.exe	85
PID 2164 wrote to memory of 3856	2164	ServApi.exe	85
PID 2164 wrote to memory of 3856	2164	ServApi.exe	85
PID 2164 wrote to memory of 3856	2164	ServApi.exe	85

C:\Program Files\Microsoft Office\Root\Office16\EXCEL.EXE
"C:\Program Files\Microsoft Office\Root\Office16\EXCEL.EXE" "C:\Users\Admin\AppData\Local\Temp\Invoice_8003346.xlsm"
1⤵
- Checks processor information in registry
- Enumerates system info in registry
- Suspicious behavior: AddClipboardFormatListener
- Suspicious use of SetWindowsHookEx
- Suspicious use of WriteProcessMemory
PID:1056
- C:\dswekerjs\dljffsrd\ServApi.exe
  "C:\dswekerjs\dljffsrd\ServApi.exe"
  2⤵
  - Executes dropped EXE
  - Loads dropped DLL
  - Suspicious use of SetThreadContext
  - Suspicious behavior: MapViewOfSection
  - Suspicious use of WriteProcessMemory
  PID:2164
- - C:\dswekerjs\dljffsrd\ServApi.exe
    "C:\dswekerjs\dljffsrd\ServApi.exe"
    3⤵
    - Executes dropped EXE
    PID:3856

Network

MITRE ATT&CK Enterprise v6

Initial Access

Execution

Persistence

Privilege Escalation

Defense Evasion

Credential Access

Discovery

Query Registry

2

T1012

System Information Discovery

3

T1082

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

Replay Monitor

Loading Replay Monitor...

Downloads

memory/1056-5-0x00007FFE80C20000-0x00007FFE80C30000-memory.dmp

Filesize
64KB

Download
memory/1056-7-0x0000022D7D360000-0x0000022D7D364000-memory.dmp

Filesize
16KB

Download
memory/1056-6-0x00007FFEA4350000-0x00007FFEA4987000-memory.dmp

Filesize
6.2MB

Download
memory/1056-2-0x00007FFE80C20000-0x00007FFE80C30000-memory.dmp

Filesize
64KB

Download
memory/1056-4-0x00007FFE80C20000-0x00007FFE80C30000-memory.dmp

Filesize
64KB

Download
memory/1056-3-0x00007FFE80C20000-0x00007FFE80C30000-memory.dmp

Filesize
64KB

Download
memory/3856-14-0x0000000040000000-0x0000000040009000-memory.dmp

Filesize
36KB

Download

Analysis

Sharing

General

Malware Config

Extracted

Signatures

Processes

Network

MITRE ATT&CK Enterprise v6

Replay Monitor

Loading Replay Monitor...

Downloads