rustybuer | 88689636f4b2287701b63f42c12e7e2387bf4c3ecc45eeb8a61ea707126bad9b

General

Target

mudminnows.exe
Size

3.2MB
MD5

106b947aa2e8101bff6e3ff0f82bfe95
SHA1

78a381408947f252bcbe170a4223c8a5a64fc11f
SHA256

88689636f4b2287701b63f42c12e7e2387bf4c3ecc45eeb8a61ea707126bad9b
SHA512

da8e58f307b7dfba78a96e1af5a4c9df79040f7d5a1181a08926bd32ff6d782375636882703d4eb6d194876c9aafd8394cde129ba401d66c5079393d84433693

Score

10^/10

rustybuer loader

Malware Config

Extracted

Family

rustybuer

C2

https://cerionetya.com/

Signatures

RustyBuer
RustyBuer is a new variant of Buer loader written in Rust.
loader rustybuer

Enumerates connected drives 3 TTPs 49 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

Processes:

secinit.exe

description	ioc	process
File opened (read-only)	\??\m:	secinit.exe
File opened (read-only)	\??\n:	secinit.exe
File opened (read-only)	\??\N:	secinit.exe
File opened (read-only)	\??\P:	secinit.exe
File opened (read-only)	\??\r:	secinit.exe
File opened (read-only)	\??\u:	secinit.exe
File opened (read-only)	\??\b:	secinit.exe
File opened (read-only)	\??\j:	secinit.exe
File opened (read-only)	\??\v:	secinit.exe
File opened (read-only)	\??\Z:	secinit.exe
File opened (read-only)	\??\W:	secinit.exe
File opened (read-only)	\??\Y:	secinit.exe
File opened (read-only)	\??\k:	secinit.exe
File opened (read-only)	\??\S:	secinit.exe
File opened (read-only)	\??\e:	secinit.exe
File opened (read-only)	\??\h:	secinit.exe
File opened (read-only)	\??\l:	secinit.exe
File opened (read-only)	\??\L:	secinit.exe
File opened (read-only)	\??\Q:	secinit.exe
File opened (read-only)	\??\s:	secinit.exe
File opened (read-only)	\??\A:	secinit.exe
File opened (read-only)	\??\B:	secinit.exe
File opened (read-only)	\??\O:	secinit.exe
File opened (read-only)	\??\q:	secinit.exe
File opened (read-only)	\??\V:	secinit.exe
File opened (read-only)	\??\E:	secinit.exe
File opened (read-only)	\??\i:	secinit.exe
File opened (read-only)	\??\z:	secinit.exe
File opened (read-only)	\??\w:	secinit.exe
File opened (read-only)	\??\x:	secinit.exe
File opened (read-only)	\??\F:	secinit.exe
File opened (read-only)	\??\G:	secinit.exe
File opened (read-only)	\??\H:	secinit.exe
File opened (read-only)	\??\J:	secinit.exe
File opened (read-only)	\??\R:	secinit.exe
File opened (read-only)	\??\T:	secinit.exe
File opened (read-only)	\??\a:	secinit.exe
File opened (read-only)	\??\D:	secinit.exe
File opened (read-only)	\??\X:	secinit.exe
File opened (read-only)	\??\y:	secinit.exe
File opened (read-only)	\??\o:	secinit.exe
File opened (read-only)	\??\t:	secinit.exe
File opened (read-only)	\??\I:	secinit.exe
File opened (read-only)	\??\M:	secinit.exe
File opened (read-only)	\??\K:	secinit.exe
File opened (read-only)	\??\p:	secinit.exe
File opened (read-only)	\??\U:	secinit.exe
File opened (read-only)	\??\f:	secinit.exe
File opened (read-only)	\??\g:	secinit.exe

Suspicious use of SetThreadContext 1 IoCs

Processes:

mudminnows.exe

description pid process target process

PID 4048 set thread context of 2932 4048 mudminnows.exe secinit.exe
Suspicious behavior: EnumeratesProcesses 2 IoCs

Processes:

secinit.exe

pid process

2932 secinit.exe
2932 secinit.exe

description	pid	process	target process
PID 4048 set thread context of 2932	4048	mudminnows.exe	secinit.exe

pid	process
2932	secinit.exe
2932	secinit.exe

Suspicious use of WriteProcessMemory 9 IoCs

Processes:

mudminnows.exe

description	pid	process	target process
PID 4048 wrote to memory of 2932	4048	mudminnows.exe	secinit.exe
PID 4048 wrote to memory of 2932	4048	mudminnows.exe	secinit.exe
PID 4048 wrote to memory of 2932	4048	mudminnows.exe	secinit.exe
PID 4048 wrote to memory of 2932	4048	mudminnows.exe	secinit.exe
PID 4048 wrote to memory of 2932	4048	mudminnows.exe	secinit.exe
PID 4048 wrote to memory of 2932	4048	mudminnows.exe	secinit.exe
PID 4048 wrote to memory of 2932	4048	mudminnows.exe	secinit.exe
PID 4048 wrote to memory of 2932	4048	mudminnows.exe	secinit.exe
PID 4048 wrote to memory of 2932	4048	mudminnows.exe	secinit.exe

C:\Users\Admin\AppData\Local\Temp\mudminnows.exe
"C:\Users\Admin\AppData\Local\Temp\mudminnows.exe"
1⤵
- Suspicious use of SetThreadContext
- Suspicious use of WriteProcessMemory
PID:4048
- C:\Windows\SysWOW64\secinit.exe
  "C:\Windows\System32\secinit.exe"
  2⤵
  - Enumerates connected drives
  - Suspicious behavior: EnumeratesProcesses
  PID:2932

Network

MITRE ATT&CK Enterprise v6

Initial Access

Execution

Persistence

Privilege Escalation

Defense Evasion

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/2932-114-0x0000000000400000-0x0000000000534000-memory.dmp

Filesize
1.2MB

Download
memory/2932-115-0x0000000000488EE4-mapping.dmp

Download
memory/2932-119-0x0000000000400000-0x0000000000534000-memory.dmp

Filesize
1.2MB

Download
memory/4048-118-0x00000000004E0000-0x00000000004E1000-memory.dmp

Filesize
4KB

Download

Analysis

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