dcrat | b4b47571926c6fb637d7ca1f9ce6e171ab98f8d63f9efb89954ca9aa10c8260b

General

Target

DCRatBuild.exe
Size

2.2MB
MD5

f961009433ca2f3a302b6a7236bc7ef4
SHA1

de9c950643db1fd43fd37d1f01db5d186a492244
SHA256

b4b47571926c6fb637d7ca1f9ce6e171ab98f8d63f9efb89954ca9aa10c8260b
SHA512

3637e15257a813ed87ad05ebc4fc28550c8440afe06e07205309c69f615e03f0cc7e318357fabe7951c729c56d079e188aad4b10e1e4feabf010e11e729875a1
SSDEEP

49152:UbA30EQtOTsSj5tM1xb5fO7jR1SaZRX62:UbFCBjHgx1fsjR1ne2

Score

10^/10

dcrat defense_evasion discovery infostealer rat trojan

Malware Config

Signatures

DcRat
DarkCrystal(DC) is a new .NET RAT active since June 2019 capable of loading additional plugins.
rat infostealer dcrat
Dcrat family
dcrat

Process spawned unexpected child process 6 IoCs

This typically indicates the parent process was compromised via an exploit or macro.

description	pid	pid_target	Process	procid_target
Parent C:\Windows\system32\wbem\wmiprvse.exe is not expected to spawn this process	2588	2740	schtasks.exe	35
Parent C:\Windows\system32\wbem\wmiprvse.exe is not expected to spawn this process	2540	2740	schtasks.exe	35
Parent C:\Windows\system32\wbem\wmiprvse.exe is not expected to spawn this process	2560	2740	schtasks.exe	35
Parent C:\Windows\system32\wbem\wmiprvse.exe is not expected to spawn this process	2928	2740	schtasks.exe	35
Parent C:\Windows\system32\wbem\wmiprvse.exe is not expected to spawn this process	2484	2740	schtasks.exe	35
Parent C:\Windows\system32\wbem\wmiprvse.exe is not expected to spawn this process	1648	2740	schtasks.exe	35

UAC bypass 3 TTPs 6 IoCs

defense_evasion trojan

Bypass User Account Control

T1548.002

Disable or Modify Tools

T1562.001

Modify Registry

T1112

description	ioc	Process
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA = "0"	BlockCrtdll.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\ConsentPromptBehaviorAdmin = "0"	BlockCrtdll.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\PromptOnSecureDesktop = "0"	BlockCrtdll.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA = "0"	dwm.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\ConsentPromptBehaviorAdmin = "0"	dwm.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\PromptOnSecureDesktop = "0"	dwm.exe

DCRat payload 3 IoCs

Detects payload of DCRat, commonly dropped by NSIS installers.

rat

resource	yara_rule
behavioral1/files/0x0006000000019217-9.dat	dcrat
behavioral1/memory/2792-13-0x0000000000F20000-0x000000000110A000-memory.dmp	dcrat
behavioral1/memory/2732-27-0x0000000000D80000-0x0000000000F6A000-memory.dmp	dcrat

Executes dropped EXE 2 IoCs

pid	Process
2792	BlockCrtdll.exe
2732	dwm.exe

Loads dropped DLL 2 IoCs

pid	Process
2772	cmd.exe
2772	cmd.exe

Checks whether UAC is enabled 1 TTPs 4 IoCs

defense_evasion trojan

System Information Discovery

T1082

description	ioc	Process
Key value queried	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA	dwm.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA = "0"	dwm.exe
Key value queried	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA	BlockCrtdll.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA = "0"	BlockCrtdll.exe

Drops file in Windows directory 3 IoCs

description	ioc	Process
File created	C:\Windows\AppCompat\Programs\dwm.exe	BlockCrtdll.exe
File opened for modification	C:\Windows\AppCompat\Programs\dwm.exe	BlockCrtdll.exe
File created	C:\Windows\AppCompat\Programs\6cb0b6c459d5d3	BlockCrtdll.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 3 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

description	ioc	Process
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	DCRatBuild.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	WScript.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	cmd.exe

Scheduled Task/Job: Scheduled Task 1 TTPs 6 IoCs

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

persistence execution

Scheduled Task

T1053.005

pid	Process
2484	schtasks.exe
1648	schtasks.exe
2588	schtasks.exe
2540	schtasks.exe
2560	schtasks.exe
2928	schtasks.exe

Suspicious behavior: EnumeratesProcesses 2 IoCs

pid	Process
2792	BlockCrtdll.exe
2732	dwm.exe

Suspicious use of AdjustPrivilegeToken 2 IoCs

description	pid	Process
Token: SeDebugPrivilege	2792	BlockCrtdll.exe
Token: SeDebugPrivilege	2732	dwm.exe

Suspicious use of WriteProcessMemory 15 IoCs

description	pid	Process	procid_target
PID 1732 wrote to memory of 2728	1732	DCRatBuild.exe	31
PID 1732 wrote to memory of 2728	1732	DCRatBuild.exe	31
PID 1732 wrote to memory of 2728	1732	DCRatBuild.exe	31
PID 1732 wrote to memory of 2728	1732	DCRatBuild.exe	31
PID 2728 wrote to memory of 2772	2728	WScript.exe	32
PID 2728 wrote to memory of 2772	2728	WScript.exe	32
PID 2728 wrote to memory of 2772	2728	WScript.exe	32
PID 2728 wrote to memory of 2772	2728	WScript.exe	32
PID 2772 wrote to memory of 2792	2772	cmd.exe	34
PID 2772 wrote to memory of 2792	2772	cmd.exe	34
PID 2772 wrote to memory of 2792	2772	cmd.exe	34
PID 2772 wrote to memory of 2792	2772	cmd.exe	34
PID 2792 wrote to memory of 2732	2792	BlockCrtdll.exe	42
PID 2792 wrote to memory of 2732	2792	BlockCrtdll.exe	42
PID 2792 wrote to memory of 2732	2792	BlockCrtdll.exe	42

System policy modification 1 TTPs 6 IoCs

defense_evasion

Modify Registry

T1112

description	ioc	Process
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\PromptOnSecureDesktop = "0"	BlockCrtdll.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA = "0"	dwm.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\ConsentPromptBehaviorAdmin = "0"	dwm.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\PromptOnSecureDesktop = "0"	dwm.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA = "0"	BlockCrtdll.exe
Set value (int)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\ConsentPromptBehaviorAdmin = "0"	BlockCrtdll.exe

Uses Task Scheduler COM API 1 TTPs
The Task Scheduler COM API can be used to schedule applications to run on boot or at set times.
persistence

Query Registry
T1012

C:\Users\Admin\AppData\Local\Temp\DCRatBuild.exe
"C:\Users\Admin\AppData\Local\Temp\DCRatBuild.exe"
1⤵
- System Location Discovery: System Language Discovery
- Suspicious use of WriteProcessMemory
PID:1732
- C:\Windows\SysWOW64\WScript.exe
  "C:\Windows\System32\WScript.exe" "C:\serverComponentDllcommon\bx6BMmKgSYwa72gSXp87543q080.vbe"
  2⤵
  - System Location Discovery: System Language Discovery
  - Suspicious use of WriteProcessMemory
  PID:2728
- - C:\Windows\SysWOW64\cmd.exe
    cmd /c ""C:\serverComponentDllcommon\zRrwLBfNMV0sSxintCMs2hsAWOJU.bat" "
    3⤵
    - Loads dropped DLL
    - System Location Discovery: System Language Discovery
    - Suspicious use of WriteProcessMemory
    PID:2772
  - - C:\serverComponentDllcommon\BlockCrtdll.exe
      "C:\serverComponentDllcommon\BlockCrtdll.exe"
      4⤵
      UAC bypass
      Executes dropped EXE
      Checks whether UAC is enabled
      Drops file in Windows directory
      Suspicious behavior: EnumeratesProcesses
      Suspicious use of AdjustPrivilegeToken
      Suspicious use of WriteProcessMemory
      System policy modification
      PID:2792
    - - C:\Windows\AppCompat\Programs\dwm.exe
        
        "C:\Windows\AppCompat\Programs\dwm.exe"
        5⤵
        UAC bypass
        Executes dropped EXE
        Checks whether UAC is enabled
        Suspicious behavior: EnumeratesProcesses
        Suspicious use of AdjustPrivilegeToken
        System policy modification
        
        PID:2732

C:\Windows\system32\schtasks.exe
schtasks.exe /create /tn "dwmd" /sc MINUTE /mo 12 /tr "'C:\Windows\AppCompat\Programs\dwm.exe'" /f
1⤵
- Process spawned unexpected child process
- Scheduled Task/Job: Scheduled Task
PID:2588

C:\Windows\system32\schtasks.exe
schtasks.exe /create /tn "dwm" /sc ONLOGON /tr "'C:\Windows\AppCompat\Programs\dwm.exe'" /rl HIGHEST /f
1⤵
- Process spawned unexpected child process
- Scheduled Task/Job: Scheduled Task
PID:2540

C:\Windows\system32\schtasks.exe
schtasks.exe /create /tn "dwmd" /sc MINUTE /mo 5 /tr "'C:\Windows\AppCompat\Programs\dwm.exe'" /rl HIGHEST /f
1⤵
- Process spawned unexpected child process
- Scheduled Task/Job: Scheduled Task
PID:2560

C:\Windows\system32\schtasks.exe
schtasks.exe /create /tn "csrssc" /sc MINUTE /mo 7 /tr "'C:\Recovery\1a287102-69f6-11ef-b2ff-62cb582c238c\csrss.exe'" /f
1⤵
- Process spawned unexpected child process
- Scheduled Task/Job: Scheduled Task
PID:2928

C:\Windows\system32\schtasks.exe
schtasks.exe /create /tn "csrss" /sc ONLOGON /tr "'C:\Recovery\1a287102-69f6-11ef-b2ff-62cb582c238c\csrss.exe'" /rl HIGHEST /f
1⤵
- Process spawned unexpected child process
- Scheduled Task/Job: Scheduled Task
PID:2484

C:\Windows\system32\schtasks.exe
schtasks.exe /create /tn "csrssc" /sc MINUTE /mo 11 /tr "'C:\Recovery\1a287102-69f6-11ef-b2ff-62cb582c238c\csrss.exe'" /rl HIGHEST /f
1⤵
- Process spawned unexpected child process
- Scheduled Task/Job: Scheduled Task
PID:1648

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

Abuse Elevation Control Mechanism

1

T1548

Bypass User Account Control

1

T1548.002

Scheduled Task/Job

1

T1053

Scheduled Task

1

T1053.005

Defense Evasion

Abuse Elevation Control Mechanism

1

T1548

Bypass User Account Control

1

T1548.002

Impair Defenses

1

T1562

Disable or Modify Tools

Modify Registry

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:\serverComponentDllcommon\bx6BMmKgSYwa72gSXp87543q080.vbe

Filesize
229B

MD5
d88322aff4ad78498de6b2f94849650b

SHA1
083dad97a0c0fb49bff2aafb71b3c2f1649b7874

SHA256
8ef333818cc91032a286af156d19dc2940e23349b59823fd321899b45411dff7

SHA512
8017b8704665def6102dc1a1ba09d6d2786ca3810160df40da980a839eff518d714bdc71677ffc3102ea60b51e034c134d78dec81d4ea69dd7ef2929055bddd7

Download Submit
C:\serverComponentDllcommon\zRrwLBfNMV0sSxintCMs2hsAWOJU.bat

Filesize
45B

MD5
f1e21d43b8f7088bb04b918c5d374889

SHA1
3af9d153963b57f317b38d543e2d49d7e5f2b024

SHA256
0734a22e43a714e98295ec0cf6fa0b801dc7634b206533a219401a9f87444fc6

SHA512
8ae8c28afaa70cbbd5c0c7395855299402552c707b3c0e1ab1cf43adb643175ac5f69063a1a8433ab2db3eae2e6c992164478d8229e35814e41f116d797f3c3b

Download Submit
\serverComponentDllcommon\BlockCrtdll.exe

Filesize
1.9MB

MD5
496e5e387972013c1cb840b3c950619a

SHA1
590ebfbeb19abe6209ce0fd443a4ddbf99bb6b06

SHA256
65c9c72f636b657567a6c266530e32fced0bd925862a8cb1a36f17ed2e5fcab9

SHA512
627852c5b9c5623d63af7e328350a12390df8dac076df5eb68e9d062af6e4b722b454f84385084f2010853c2af0a78b1ae7eab5a04e75a522308bc5d196ca064

Download Submit
memory/2732-27-0x0000000000D80000-0x0000000000F6A000-memory.dmp

Filesize
1.9MB

Download
memory/2792-13-0x0000000000F20000-0x000000000110A000-memory.dmp

Filesize
1.9MB

Download
memory/2792-14-0x0000000000450000-0x000000000045A000-memory.dmp

Filesize
40KB

Download
memory/2792-15-0x0000000000B70000-0x0000000000BC6000-memory.dmp

Filesize
344KB

Download
memory/2792-16-0x0000000000460000-0x000000000046C000-memory.dmp

Filesize
48KB

Download

Analysis

Sharing

General

Malware Config

Signatures

Processes

Network

MITRE ATT&CK Enterprise v15

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Downloads