asyncrat | 8a42ea3258ea46d5e218afe6d72080d7b7b891175220a1aab084b6a64735c4bd

General

Target

AsyncClient.exe
Size

164KB
MD5

b7a6d85bc95cb3b089057068c30f2d8b
SHA1

864f88d3a1622e8ff48ea48e0c0efb639c079ee8
SHA256

8a42ea3258ea46d5e218afe6d72080d7b7b891175220a1aab084b6a64735c4bd
SHA512

e78f62936c0981a26722c6850f1e4b0e4b3befc8298d34cd0e63ec59615554dea2c402a1b81947e0ca1f9a883a6cacdb9901b02a1b99c371c26588fbdd3d1632
SSDEEP

3072:iuQET/Lm2QskDy3bCgpf1bz8fvFG6GGGGGGGGGGGGGGGGGGG7sGGGGGJFpx:iuQ+TQO3bVhFg9G6GGGGGGGGGGGGGGGl

Score

10^/10

asyncrat default discovery rat

Malware Config

Extracted

Family

asyncrat

Version

0.5.8

Botnet

Default

C2

127.0.0.1:6606

127.0.0.1:7707

127.0.0.1:8808

Mutex

O4aZIBt8sGlP

Attributes

delay
3
install
true
install_file
a.exe
install_folder
%AppData%

aes.plain

Signatures

AsyncRat
AsyncRAT is designed to remotely monitor and control other computers written in C#.
rat asyncrat
Asyncrat family
asyncrat

Async RAT payload 1 IoCs

rat

Processes:

resource	yara_rule
behavioral2/files/0x000a000000023c73-11.dat	family_asyncrat

Checks computer location settings 2 TTPs 1 IoCs

Looks up country code configured in the registry, likely geofence.

Query Registry

T1012

System Information Discovery

T1082

Processes:

AsyncClient.exe

description	ioc	Process
Key value queried	\REGISTRY\USER\S-1-5-21-2045521122-590294423-3465680274-1000\Control Panel\International\Geo\Nation	AsyncClient.exe

Executes dropped EXE 1 IoCs

Processes:

a.exe

pid	Process
4296	a.exe

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

System Information Discovery
T1082

System Location Discovery: System Language Discovery 1 TTPs 6 IoCs

Attempt gather information about the system language of a victim in order to infer the geographical location of that host.

discovery

System Language Discovery

T1614.001

Processes:

AsyncClient.execmd.execmd.exetimeout.exeschtasks.exea.exe

description	ioc	Process
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	AsyncClient.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	cmd.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	cmd.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	timeout.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	schtasks.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	a.exe

Delays execution with timeout.exe 1 IoCs

evasion

Processes:

timeout.exe

pid	Process
1136	timeout.exe

Scheduled Task/Job: Scheduled Task 1 TTPs 1 IoCs

Schtasks is often used by malware for persistence or to perform post-infection execution.

persistence execution

Scheduled Task

T1053.005

Processes:

schtasks.exe

pid	Process
1308	schtasks.exe

Suspicious behavior: EnumeratesProcesses 23 IoCs

Processes:

AsyncClient.exe

pid	Process
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe
3612	AsyncClient.exe

Suspicious use of AdjustPrivilegeToken 2 IoCs

Processes:

AsyncClient.exea.exe

description	pid	Process
Token: SeDebugPrivilege	3612	AsyncClient.exe
Token: SeDebugPrivilege	4296	a.exe

Suspicious use of WriteProcessMemory 15 IoCs

Processes:

AsyncClient.execmd.execmd.exe

description	pid	Process	procid_target
PID 3612 wrote to memory of 4816	3612	AsyncClient.exe	84
PID 3612 wrote to memory of 4816	3612	AsyncClient.exe	84
PID 3612 wrote to memory of 4816	3612	AsyncClient.exe	84
PID 3612 wrote to memory of 1948	3612	AsyncClient.exe	86
PID 3612 wrote to memory of 1948	3612	AsyncClient.exe	86
PID 3612 wrote to memory of 1948	3612	AsyncClient.exe	86
PID 1948 wrote to memory of 1136	1948	cmd.exe	88
PID 1948 wrote to memory of 1136	1948	cmd.exe	88
PID 1948 wrote to memory of 1136	1948	cmd.exe	88
PID 4816 wrote to memory of 1308	4816	cmd.exe	89
PID 4816 wrote to memory of 1308	4816	cmd.exe	89
PID 4816 wrote to memory of 1308	4816	cmd.exe	89
PID 1948 wrote to memory of 4296	1948	cmd.exe	91
PID 1948 wrote to memory of 4296	1948	cmd.exe	91
PID 1948 wrote to memory of 4296	1948	cmd.exe	91

C:\Users\Admin\AppData\Local\Temp\AsyncClient.exe
"C:\Users\Admin\AppData\Local\Temp\AsyncClient.exe"
1⤵
- Checks computer location settings
- System Location Discovery: System Language Discovery
- Suspicious behavior: EnumeratesProcesses
- Suspicious use of AdjustPrivilegeToken
- Suspicious use of WriteProcessMemory
PID:3612
- C:\Windows\SysWOW64\cmd.exe
  "C:\Windows\System32\cmd.exe" /c schtasks /create /f /sc onlogon /rl highest /tn "a" /tr '"C:\Users\Admin\AppData\Roaming\a.exe"' & exit
  2⤵
  - System Location Discovery: System Language Discovery
  - Suspicious use of WriteProcessMemory
  PID:4816
- - C:\Windows\SysWOW64\schtasks.exe
    schtasks /create /f /sc onlogon /rl highest /tn "a" /tr '"C:\Users\Admin\AppData\Roaming\a.exe"'
    3⤵
    - System Location Discovery: System Language Discovery
    - Scheduled Task/Job: Scheduled Task
    PID:1308
- C:\Windows\SysWOW64\cmd.exe
  C:\Windows\system32\cmd.exe /c ""C:\Users\Admin\AppData\Local\Temp\tmpB67F.tmp.bat""
  2⤵
  - System Location Discovery: System Language Discovery
  - Suspicious use of WriteProcessMemory
  PID:1948
- - C:\Windows\SysWOW64\timeout.exe
    timeout 3
    3⤵
    - System Location Discovery: System Language Discovery
    - Delays execution with timeout.exe
    PID:1136
- - C:\Users\Admin\AppData\Roaming\a.exe
    "C:\Users\Admin\AppData\Roaming\a.exe"
    3⤵
    - Executes dropped EXE
    - System Location Discovery: System Language Discovery
    - Suspicious use of AdjustPrivilegeToken
    PID:4296

Network

MITRE ATT&CK Enterprise v15

Reconnaissance

Resource Development

Initial Access

Execution

Scheduled Task/Job

1

T1053

Scheduled Task

1

T1053.005

Persistence

Scheduled Task/Job

1

T1053

Scheduled Task

1

T1053.005

Privilege Escalation

Scheduled Task/Job

1

T1053

Scheduled Task

1

T1053.005

Defense Evasion

Credential Access

Discovery

Query Registry

1

T1012

System Information Discovery

2

T1082

System Location Discovery

1

T1614

System Language Discovery

1

T1614.001

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

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Downloads

C:\Users\Admin\AppData\Local\Temp\tmpB67F.tmp.bat

Filesize
145B

MD5
64ac21bf04c0745f5afed4b8cc8bdb61

SHA1
9c6e8dc5402398f61b092ede777fc733a6918e62

SHA256
b743196ac395deec72b3ee9a257f08b69352a22f1c5047d4690af74e1a88ba34

SHA512
a23e05ab69e60c27ddd85fb2b4e43ae155912d0b0cf86b77f830417334084465d7df69e7a0cf1316bc4911372337d2b1b17e73f3478c13adc4e03c539fb4279f

Download Submit
C:\Users\Admin\AppData\Roaming\a.exe

Filesize
164KB

MD5
b7a6d85bc95cb3b089057068c30f2d8b

SHA1
864f88d3a1622e8ff48ea48e0c0efb639c079ee8

SHA256
8a42ea3258ea46d5e218afe6d72080d7b7b891175220a1aab084b6a64735c4bd

SHA512
e78f62936c0981a26722c6850f1e4b0e4b3befc8298d34cd0e63ec59615554dea2c402a1b81947e0ca1f9a883a6cacdb9901b02a1b99c371c26588fbdd3d1632

Download Submit
memory/3612-0-0x000000007449E000-0x000000007449F000-memory.dmp

Filesize
4KB

Download
memory/3612-1-0x0000000000C40000-0x0000000000C70000-memory.dmp

Filesize
192KB

Download
memory/3612-2-0x0000000074490000-0x0000000074C40000-memory.dmp

Filesize
7.7MB

Download
memory/3612-3-0x0000000005620000-0x00000000056BC000-memory.dmp

Filesize
624KB

Download
memory/3612-8-0x0000000074490000-0x0000000074C40000-memory.dmp

Filesize
7.7MB

Download
memory/4296-13-0x00000000743E0000-0x0000000074B90000-memory.dmp

Filesize
7.7MB

Download
memory/4296-14-0x00000000743E0000-0x0000000074B90000-memory.dmp

Filesize
7.7MB

Download

Analysis

Sharing

General

Malware Config

Extracted

Signatures

Processes

Network

MITRE ATT&CK Enterprise v15

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Downloads