buer | a9ec36c1b7687d5436007f2640795702ec68b69a67561f94e8507857eb1971cd

Analysis

max time kernel
15s
max time network
112s
platform
windows10_x64
resource
win10v20201028
submitted
05-03-2021 18:22

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General

Target

OfficeDocument.exe
Size

277KB
MD5

50991ebb9f7b1eb055901dc643bf50c5
SHA1

366e13a36809fef35d12e46b3f14ce950de6a7c0
SHA256

a9ec36c1b7687d5436007f2640795702ec68b69a67561f94e8507857eb1971cd
SHA512

3b5388273e490433b9bef0c445dccb628c89be7568effe0bc3f709f3f1bb021f1881846ddc96831a201b74246be87c6404acaebe9f20be6d19b74797f0a903f0

Score

10^/10

buer loader

Malware Config

Extracted

Family

buer

officesecuredocapi.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.

Processes:

resource	yara_rule
behavioral2/memory/1120-4-0x0000000040000000-0x0000000040009000-memory.dmp	buer

Loads dropped DLL 1 IoCs

Processes:

OfficeDocument.exe

pid process

4772 OfficeDocument.exe
Suspicious use of SetThreadContext 1 IoCs

Processes:

OfficeDocument.exe

description pid process target process

PID 4772 set thread context of 1120 4772 OfficeDocument.exe OfficeDocument.exe
Enumerates physical storage devices 1 TTPs
Attempts to interact with connected storage/optical drive(s). Likely ransomware behaviour.

System Information Discovery
T1082
Suspicious behavior: MapViewOfSection 1 IoCs

Processes:

OfficeDocument.exe

pid process

4772 OfficeDocument.exe

pid	process
4772	OfficeDocument.exe

description	pid	process	target process
PID 4772 set thread context of 1120	4772	OfficeDocument.exe	OfficeDocument.exe

pid	process
4772	OfficeDocument.exe

Suspicious use of WriteProcessMemory 4 IoCs

Processes:

OfficeDocument.exe

description	pid	process	target process
PID 4772 wrote to memory of 1120	4772	OfficeDocument.exe	OfficeDocument.exe
PID 4772 wrote to memory of 1120	4772	OfficeDocument.exe	OfficeDocument.exe
PID 4772 wrote to memory of 1120	4772	OfficeDocument.exe	OfficeDocument.exe
PID 4772 wrote to memory of 1120	4772	OfficeDocument.exe	OfficeDocument.exe

C:\Users\Admin\AppData\Local\Temp\OfficeDocument.exe
"C:\Users\Admin\AppData\Local\Temp\OfficeDocument.exe"
1⤵
- Loads dropped DLL
- Suspicious use of SetThreadContext
- Suspicious behavior: MapViewOfSection
- Suspicious use of WriteProcessMemory
PID:4772

C:\Users\Admin\AppData\Local\Temp\OfficeDocument.exe
"C:\Users\Admin\AppData\Local\Temp\OfficeDocument.exe"
2⤵
PID:1120

MITRE ATT&CK Matrix ATT&CK v6

Initial Access

Execution

Persistence

Privilege Escalation

Defense Evasion

Credential Access

Discovery

System Information Discovery

T1082

Lateral Movement

Collection

Exfiltration

Command and Control

Impact

Replay Monitor

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Downloads

\Users\Admin\AppData\Local\Temp\nsy4F5F.tmp\System.dll
MD5
0063d48afe5a0cdc02833145667b6641

SHA1
e7eb614805d183ecb1127c62decb1a6be1b4f7a8

SHA256
ac9dfe3b35ea4b8932536ed7406c29a432976b685cc5322f94ef93df920fede7

SHA512
71cbbcaeb345e09306e368717ea0503fe8df485be2e95200febc61bcd8ba74fb4211cd263c232f148c0123f6c6f2e3fd4ea20bdecc4070f5208c35c6920240f0

Download Submit
memory/1120-3-0x0000000040005EFA-mapping.dmp

Download
memory/1120-4-0x0000000040000000-0x0000000040009000-memory.dmp

Filesize
36KB

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