dcrat | 50ba49f457fa7dad0a39dbf75d14570d5308b33b1c4141e37223dda5c731f4b9 | Triage

Analysis

max time kernel
121s
max time network
123s
platform
windows7_x64
resource
win7-20241023-en
resource tags

arch:x64arch:x86image:win7-20241023-enlocale:en-usos:windows7-x64system
submitted
27/01/2025, 18:22 UTC

Sharing

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General

Target

Serversvc.exe
Size

827KB
MD5

2b1b671bc3ef38079bfc62e0383258e8
SHA1

1231c2d534a55d0e0923953e3d238a2052d6fad7
SHA256

50ba49f457fa7dad0a39dbf75d14570d5308b33b1c4141e37223dda5c731f4b9
SHA512

0552db872a39c27e069a6526db6046368887fc2fc42534ab63fb30ed235388cf831b52bec5234b2fb2bec50f774fe17d31a27323b702f03029233d6a1b9d5f23
SSDEEP

12288:YlMOe0Zu4AanEAlKOP6dE1qAmpBfcjYbg4EEgIGSXx9GI:Ye0Zu4AarrP2OCm4g41Zf

Score

10^/10

dcrat infostealer persistence rat

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

Modifies WinLogon for persistence 2 TTPs 1 IoCs

Winlogon Helper DLL

Modify Registry

description	ioc	Process
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell = "explorer.exe, \"C:/Users/Admin/AppData/Local/\\dllhost.exe\""	Serversvc.exe

Process spawned unexpected child process 3 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	2900	3056	schtasks.exe	30
Parent C:\Windows\system32\wbem\wmiprvse.exe is not expected to spawn this process	2536	3056	schtasks.exe	30
Parent C:\Windows\system32\wbem\wmiprvse.exe is not expected to spawn this process	2228	3056	schtasks.exe	30

DCRat payload 3 IoCs

Detects payload of DCRat, commonly dropped by NSIS installers.

resource	yara_rule
behavioral1/memory/1124-1-0x0000000000230000-0x0000000000306000-memory.dmp	dcrat
behavioral1/files/0x000d0000000122de-9.dat	dcrat
behavioral1/memory/2784-13-0x0000000000830000-0x0000000000906000-memory.dmp	dcrat

Executes dropped EXE 1 IoCs

pid	Process
2784	dllhost.exe

Adds Run key to start application 2 TTPs 2 IoCs

Registry Run Keys / Startup Folder

Modify Registry

description	ioc	Process
Set value (str)	\REGISTRY\USER\S-1-5-21-1163522206-1469769407-485553996-1000\Software\Microsoft\Windows\CurrentVersion\Run\dllhost = "\"C:/Users/Admin/AppData/Local/\\dllhost.exe\""	Serversvc.exe
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\dllhost = "\"C:/Users/Admin/AppData/Local/\\dllhost.exe\""	Serversvc.exe

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

System Information Discovery
T1082

Scheduled Task/Job: Scheduled Task 1 TTPs 3 IoCs

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

persistence execution

Scheduled Task

pid	Process
2900	schtasks.exe
2536	schtasks.exe
2228	schtasks.exe

Suspicious behavior: EnumeratesProcesses 2 IoCs

pid	Process
1124	Serversvc.exe
2784	dllhost.exe

Suspicious use of AdjustPrivilegeToken 2 IoCs

description	pid	Process
Token: SeDebugPrivilege	1124	Serversvc.exe
Token: SeDebugPrivilege	2784	dllhost.exe

Suspicious use of WriteProcessMemory 3 IoCs

description	pid	Process	procid_target
PID 1124 wrote to memory of 2784	1124	Serversvc.exe	34
PID 1124 wrote to memory of 2784	1124	Serversvc.exe	34
PID 1124 wrote to memory of 2784	1124	Serversvc.exe	34

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\Serversvc.exe
"C:\Users\Admin\AppData\Local\Temp\Serversvc.exe"
1⤵
- Modifies WinLogon for persistence
- Adds Run key to start application
- Suspicious behavior: EnumeratesProcesses
- Suspicious use of AdjustPrivilegeToken
- Suspicious use of WriteProcessMemory
PID:1124
- C:\Users\Admin\AppData\Local\dllhost.exe
  "C:\Users\Admin\AppData\Local\dllhost.exe"
  2⤵
  - Executes dropped EXE
  - Suspicious behavior: EnumeratesProcesses
  - Suspicious use of AdjustPrivilegeToken
  PID:2784

C:\Windows\system32\schtasks.exe
schtasks.exe /create /tn "dllhostd" /sc MINUTE /mo 14 /tr "'C:/Users/Admin/AppData/Local/\dllhost.exe'" /f
1⤵
- Process spawned unexpected child process
- Scheduled Task/Job: Scheduled Task
PID:2900

C:\Windows\system32\schtasks.exe
schtasks.exe /create /tn "dllhost" /sc ONLOGON /tr "'C:/Users/Admin/AppData/Local/\dllhost.exe'" /rl HIGHEST /f
1⤵
- Process spawned unexpected child process
- Scheduled Task/Job: Scheduled Task
PID:2536

C:\Windows\system32\schtasks.exe
schtasks.exe /create /tn "dllhostd" /sc MINUTE /mo 9 /tr "'C:/Users/Admin/AppData/Local/\dllhost.exe'" /rl HIGHEST /f
1⤵
- Process spawned unexpected child process
- Scheduled Task/Job: Scheduled Task
PID:2228

Network

DNS

cf83712.tw1.ru

dllhost.exe

Remote address:

8.8.8.8:53

Request

cf83712.tw1.ru

IN A

Response

cf83712.tw1.ru

IN A

94.198.223.74

94.198.223.74:80

cf83712.tw1.ru

dllhost.exe

152 B
3
94.198.223.74:80

cf83712.tw1.ru

dllhost.exe

152 B
3

8.8.8.8:53

cf83712.tw1.ru

dns

dllhost.exe

60 B
76 B
1
1

DNS Request

cf83712.tw1.ru

DNS Response

94.198.223.74

MITRE ATT&CK Enterprise v15

Reconnaissance

Resource Development

Initial Access

Execution

Scheduled Task/Job

Scheduled Task

Persistence

Boot or Logon Autostart Execution

Registry Run Keys / Startup Folder

Winlogon Helper DLL

Scheduled Task/Job

Scheduled Task

Privilege Escalation

Boot or Logon Autostart Execution

Registry Run Keys / Startup Folder

Winlogon Helper DLL

Scheduled Task/Job

Scheduled Task

Defense Evasion

Modify Registry

Credential Access

Discovery

Query Registry

System Information Discovery

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

Replay Monitor

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Downloads

C:\Users\Admin\AppData\Local\dllhost.exe

Filesize
827KB

MD5
2b1b671bc3ef38079bfc62e0383258e8

SHA1
1231c2d534a55d0e0923953e3d238a2052d6fad7

SHA256
50ba49f457fa7dad0a39dbf75d14570d5308b33b1c4141e37223dda5c731f4b9

SHA512
0552db872a39c27e069a6526db6046368887fc2fc42534ab63fb30ed235388cf831b52bec5234b2fb2bec50f774fe17d31a27323b702f03029233d6a1b9d5f23

Download Submit
memory/1124-0-0x000007FEF5D13000-0x000007FEF5D14000-memory.dmp

Filesize
4KB

Download
memory/1124-1-0x0000000000230000-0x0000000000306000-memory.dmp

Filesize
856KB

Download
memory/1124-2-0x000007FEF5D10000-0x000007FEF66FC000-memory.dmp

Filesize
9.9MB

Download
memory/1124-12-0x000007FEF5D10000-0x000007FEF66FC000-memory.dmp

Filesize
9.9MB

Download
memory/2784-13-0x0000000000830000-0x0000000000906000-memory.dmp

Filesize
856KB

Download