oski | c30ce79d7b5b0708dc03f1532fa89afd4efd732531cb557dc31fe63acd5bc1ce

General

Target

gunzipped.exe
Size

411KB
MD5

c2301b62539adcba29dcf6a3200bd017
SHA1

fd80f7e8e32661d5ec12e7a901f22a9ed82e17a7
SHA256

c30ce79d7b5b0708dc03f1532fa89afd4efd732531cb557dc31fe63acd5bc1ce
SHA512

80fef672e7f48640c585f12408025ea06c67344551bb4638e10120ceb30da7e888b18a52aabd209186315c1476da905afe15d5cb68a7d7e266954de16e813037

Score

10^/10

oski discovery infostealer spyware stealer suricata

Malware Config

Extracted

Family

oski

C2

http://2.56.57.108/osk/

Signatures

Oski
Oski is an infostealer targeting browser data, crypto wallets.
infostealer oski
suricata: ET MALWARE Suspicious Zipped Filename in Outbound POST Request (Passwords.txt)
suricata: ET MALWARE Suspicious Zipped Filename in Outbound POST Request (Passwords.txt)
suricata
suricata: ET MALWARE Vidar/Arkei/Megumin/Oski Stealer Data Exfil
suricata: ET MALWARE Vidar/Arkei/Megumin/Oski Stealer Data Exfil
suricata
suricata: ET MALWARE Vidar/Arkei/Megumin/Oski Stealer HTTP POST Pattern
suricata: ET MALWARE Vidar/Arkei/Megumin/Oski Stealer HTTP POST Pattern
suricata
Downloads MZ/PE file
Loads dropped DLL 4 IoCs

Processes:

gunzipped.exegunzipped.exe

pid process

3796 gunzipped.exe
380 gunzipped.exe
380 gunzipped.exe
380 gunzipped.exe
Reads user/profile data of web browsers 2 TTPs
Infostealers often target stored browser data, which can include saved credentials etc.
spyware stealer

Data from Local System
T1005

Credentials in Files
T1081
Accesses cryptocurrency files/wallets, possible credential harvesting 2 TTPs
spyware

Data from Local System
T1005

Credentials in Files
T1081
Checks installed software on the system 1 TTPs
Looks up Uninstall key entries in the registry to enumerate software on the system.
discovery

Query Registry
T1012
Enumerates physical storage devices 1 TTPs
Attempts to interact with connected storage/optical drive(s). Likely ransomware behaviour.

System Information Discovery
T1082
Checks processor information in registry 2 TTPs 1 IoCs
Processor information is often read in order to detect sandboxing environments.

Query Registry
T1012

System Information Discovery
T1082

Processes:

gunzipped.exe

description ioc process

Key value queried \REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0\ProcessorNameString gunzipped.exe
Kills process with taskkill 1 IoCs
evasion

Processes:

taskkill.exe

pid process

3648 taskkill.exe
Suspicious use of AdjustPrivilegeToken 1 IoCs

Processes:

taskkill.exe

description pid process

Token: SeDebugPrivilege 3648 taskkill.exe

pid	process
3796	gunzipped.exe
380	gunzipped.exe
380	gunzipped.exe
380	gunzipped.exe

description	ioc	process
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0\ProcessorNameString	gunzipped.exe

pid	process
3648	taskkill.exe

description	pid	process
Token: SeDebugPrivilege	3648	taskkill.exe

Suspicious use of WriteProcessMemory 15 IoCs

Processes:

gunzipped.exegunzipped.execmd.exe

description	pid	process	target process
PID 3796 wrote to memory of 380	3796	gunzipped.exe	gunzipped.exe
PID 3796 wrote to memory of 380	3796	gunzipped.exe	gunzipped.exe
PID 3796 wrote to memory of 380	3796	gunzipped.exe	gunzipped.exe
PID 3796 wrote to memory of 380	3796	gunzipped.exe	gunzipped.exe
PID 3796 wrote to memory of 380	3796	gunzipped.exe	gunzipped.exe
PID 3796 wrote to memory of 380	3796	gunzipped.exe	gunzipped.exe
PID 3796 wrote to memory of 380	3796	gunzipped.exe	gunzipped.exe
PID 3796 wrote to memory of 380	3796	gunzipped.exe	gunzipped.exe
PID 3796 wrote to memory of 380	3796	gunzipped.exe	gunzipped.exe
PID 380 wrote to memory of 1484	380	gunzipped.exe	cmd.exe
PID 380 wrote to memory of 1484	380	gunzipped.exe	cmd.exe
PID 380 wrote to memory of 1484	380	gunzipped.exe	cmd.exe
PID 1484 wrote to memory of 3648	1484	cmd.exe	taskkill.exe
PID 1484 wrote to memory of 3648	1484	cmd.exe	taskkill.exe
PID 1484 wrote to memory of 3648	1484	cmd.exe	taskkill.exe

C:\Users\Admin\AppData\Local\Temp\gunzipped.exe
"C:\Users\Admin\AppData\Local\Temp\gunzipped.exe"
1⤵
- Loads dropped DLL
- Suspicious use of WriteProcessMemory
PID:3796

C:\Users\Admin\AppData\Local\Temp\gunzipped.exe
"C:\Users\Admin\AppData\Local\Temp\gunzipped.exe"
2⤵
- Loads dropped DLL
- Checks processor information in registry
- Suspicious use of WriteProcessMemory
PID:380

C:\Windows\SysWOW64\cmd.exe
"C:\Windows\System32\cmd.exe" /c taskkill /pid 380 & erase C:\Users\Admin\AppData\Local\Temp\gunzipped.exe & RD /S /Q C:\\ProgramData\\531228198980345\\* & exit
3⤵
- Suspicious use of WriteProcessMemory
PID:1484

C:\Windows\SysWOW64\taskkill.exe
taskkill /pid 380
4⤵
- Kills process with taskkill
- Suspicious use of AdjustPrivilegeToken
PID:3648

Network

MITRE ATT&CK Matrix ATT&CK v6

Initial Access

Execution

Persistence

Privilege Escalation

Defense Evasion

Credential Access

Credentials in Files

2

T1081

Discovery

Query Registry

2

T1012

System Information Discovery

2

T1082

Lateral Movement

Collection

Data from Local System

2

T1005

Exfiltration

Command and Control

Impact

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Downloads

\ProgramData\mozglue.dll
MD5
8f73c08a9660691143661bf7332c3c27

SHA1
37fa65dd737c50fda710fdbde89e51374d0c204a

SHA256
3fe6b1c54b8cf28f571e0c5d6636b4069a8ab00b4f11dd842cfec00691d0c9cd

SHA512
0042ecf9b3571bb5eba2de893e8b2371df18f7c5a589f52ee66e4bfbaa15a5b8b7cc6a155792aaa8988528c27196896d5e82e1751c998bacea0d92395f66ad89

Download Submit
\ProgramData\nss3.dll
MD5
bfac4e3c5908856ba17d41edcd455a51

SHA1
8eec7e888767aa9e4cca8ff246eb2aacb9170428

SHA256
e2935b5b28550d47dc971f456d6961f20d1633b4892998750140e0eaa9ae9d78

SHA512
2565bab776c4d732ffb1f9b415992a4c65b81bcd644a9a1df1333a269e322925fc1df4f76913463296efd7c88ef194c3056de2f1ca1357d7b5fe5ff0da877a66

Download Submit
\ProgramData\sqlite3.dll
MD5
e477a96c8f2b18d6b5c27bde49c990bf

SHA1
e980c9bf41330d1e5bd04556db4646a0210f7409

SHA256
16574f51785b0e2fc29c2c61477eb47bb39f714829999511dc8952b43ab17660

SHA512
335a86268e7c0e568b1c30981ec644e6cd332e66f96d2551b58a82515316693c1859d87b4f4b7310cf1ac386cee671580fdd999c3bcb23acf2c2282c01c8798c

Download Submit
\Users\Admin\AppData\Local\Temp\nsuFEB.tmp\qhvek.dll
MD5
e1821b88ae16db674b9a0d7e3c1eabeb

SHA1
966b2fd636a330b3812c8aae9ce7a12d98e105b7

SHA256
b570a242266192cdb433f2af8e5fc2b54368dcf6f2f385dfd836032403ef4520

SHA512
c514ca0d44c63c03b6ac34e66005cbf80e5f09cd511c7fbe11ff176720ad45bfe9d2809132f6ecd0251bb22e06e6d9e19361960913707dc958eae5f115ed22f6

Download Submit
memory/380-116-0x0000000000000000-mapping.dmp

Download
memory/380-117-0x00000000007B0000-0x00000000007E8000-memory.dmp

Filesize
224KB

Download
memory/380-120-0x00000000007B0000-0x00000000007E8000-memory.dmp

Filesize
224KB

Download
memory/1484-124-0x0000000000000000-mapping.dmp

Download
memory/3648-125-0x0000000000000000-mapping.dmp

Download

Analysis

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