Analysis
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max time kernel
61s -
max time network
64s -
platform
windows7_x64 -
resource
win7-20220718-en -
resource tags
arch:x64arch:x86image:win7-20220718-enlocale:en-usos:windows7-x64system -
submitted
27-07-2022 15:07
Static task
static1
Behavioral task
behavioral1
Sample
gunzipped.exe
Resource
win7-20220718-en
Behavioral task
behavioral2
Sample
gunzipped.exe
Resource
win10v2004-20220721-en
General
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Target
gunzipped.exe
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Size
730KB
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MD5
02c69e67c2f23c547d0022147da9fbe9
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SHA1
6686b9d64df9a2c31f61c5a6682b2d899ab1a599
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SHA256
c87ec3f9dfb87a10f1c38102a3c58bc2cbb252891b5c882f3c4f3f0a9058b170
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SHA512
7fcd69e6b1eb521200d7111ff120f9fb2b67ff76f3bb49372781a9469224831ca21aad0955e1b72bd98d677450c8726053601b703818a8573e4cded9b3950c73
Malware Config
Extracted
oski
master101work.co
Signatures
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Oski
Oski is an infostealer targeting browser data, crypto wallets.
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Downloads MZ/PE file
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Deletes itself 1 IoCs
Processes:
cmd.exepid process 864 cmd.exe -
Loads dropped DLL 3 IoCs
Processes:
gunzipped.exepid process 468 gunzipped.exe 468 gunzipped.exe 468 gunzipped.exe -
Reads user/profile data of web browsers 2 TTPs
Infostealers often target stored browser data, which can include saved credentials etc.
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Accesses cryptocurrency files/wallets, possible credential harvesting 2 TTPs
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Checks installed software on the system 1 TTPs
Looks up Uninstall key entries in the registry to enumerate software on the system.
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Suspicious use of SetThreadContext 1 IoCs
Processes:
gunzipped.exedescription pid process target process PID 2032 set thread context of 468 2032 gunzipped.exe gunzipped.exe -
Enumerates physical storage devices 1 TTPs
Attempts to interact with connected storage/optical drive(s). Likely ransomware behaviour.
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Checks processor information in registry 2 TTPs 1 IoCs
Processor information is often read in order to detect sandboxing environments.
Processes:
gunzipped.exedescription ioc process Key value queried \REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0\ProcessorNameString gunzipped.exe -
Creates scheduled task(s) 1 TTPs 1 IoCs
Schtasks is often used by malware for persistence or to perform post-infection execution.
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Kills process with taskkill 1 IoCs
Processes:
taskkill.exepid process 680 taskkill.exe -
Suspicious behavior: EnumeratesProcesses 1 IoCs
Processes:
powershell.exepid process 1324 powershell.exe -
Suspicious use of AdjustPrivilegeToken 2 IoCs
Processes:
powershell.exetaskkill.exedescription pid process Token: SeDebugPrivilege 1324 powershell.exe Token: SeDebugPrivilege 680 taskkill.exe -
Suspicious use of WriteProcessMemory 26 IoCs
Processes:
gunzipped.exegunzipped.execmd.exedescription pid process target process PID 2032 wrote to memory of 1324 2032 gunzipped.exe powershell.exe PID 2032 wrote to memory of 1324 2032 gunzipped.exe powershell.exe PID 2032 wrote to memory of 1324 2032 gunzipped.exe powershell.exe PID 2032 wrote to memory of 1324 2032 gunzipped.exe powershell.exe PID 2032 wrote to memory of 1328 2032 gunzipped.exe schtasks.exe PID 2032 wrote to memory of 1328 2032 gunzipped.exe schtasks.exe PID 2032 wrote to memory of 1328 2032 gunzipped.exe schtasks.exe PID 2032 wrote to memory of 1328 2032 gunzipped.exe schtasks.exe PID 2032 wrote to memory of 468 2032 gunzipped.exe gunzipped.exe PID 2032 wrote to memory of 468 2032 gunzipped.exe gunzipped.exe PID 2032 wrote to memory of 468 2032 gunzipped.exe gunzipped.exe PID 2032 wrote to memory of 468 2032 gunzipped.exe gunzipped.exe PID 2032 wrote to memory of 468 2032 gunzipped.exe gunzipped.exe PID 2032 wrote to memory of 468 2032 gunzipped.exe gunzipped.exe PID 2032 wrote to memory of 468 2032 gunzipped.exe gunzipped.exe PID 2032 wrote to memory of 468 2032 gunzipped.exe gunzipped.exe PID 2032 wrote to memory of 468 2032 gunzipped.exe gunzipped.exe PID 2032 wrote to memory of 468 2032 gunzipped.exe gunzipped.exe PID 468 wrote to memory of 864 468 gunzipped.exe cmd.exe PID 468 wrote to memory of 864 468 gunzipped.exe cmd.exe PID 468 wrote to memory of 864 468 gunzipped.exe cmd.exe PID 468 wrote to memory of 864 468 gunzipped.exe cmd.exe PID 864 wrote to memory of 680 864 cmd.exe taskkill.exe PID 864 wrote to memory of 680 864 cmd.exe taskkill.exe PID 864 wrote to memory of 680 864 cmd.exe taskkill.exe PID 864 wrote to memory of 680 864 cmd.exe taskkill.exe
Processes
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C:\Users\Admin\AppData\Local\Temp\gunzipped.exe"C:\Users\Admin\AppData\Local\Temp\gunzipped.exe"1⤵
- Suspicious use of SetThreadContext
- Suspicious use of WriteProcessMemory
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C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe"C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" Add-MpPreference -ExclusionPath "C:\Users\Admin\AppData\Roaming\yGkHpD.exe"2⤵
- Suspicious behavior: EnumeratesProcesses
- Suspicious use of AdjustPrivilegeToken
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C:\Windows\SysWOW64\schtasks.exe"C:\Windows\System32\schtasks.exe" /Create /TN "Updates\yGkHpD" /XML "C:\Users\Admin\AppData\Local\Temp\tmpAAE0.tmp"2⤵
- Creates scheduled task(s)
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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
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C:\Windows\SysWOW64\cmd.exe"C:\Windows\System32\cmd.exe" /c taskkill /pid 468 & erase C:\Users\Admin\AppData\Local\Temp\gunzipped.exe & RD /S /Q C:\\ProgramData\\174229849002886\\* & exit3⤵
- Deletes itself
- Suspicious use of WriteProcessMemory
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C:\Windows\SysWOW64\taskkill.exetaskkill /pid 4684⤵
- Kills process with taskkill
- Suspicious use of AdjustPrivilegeToken
Network
MITRE ATT&CK Matrix ATT&CK v6
Replay Monitor
Loading Replay Monitor...
Downloads
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C:\Users\Admin\AppData\Local\Temp\tmpAAE0.tmpFilesize
1KB
MD5453532723cadf909112223ae2acfcc68
SHA173f7ede509c63175c9dbee775d9207af205ac0ef
SHA2569887a9b79c84c31bbe4c763ee36a7711546ce6cd0bb4d8f0d32d9e4b13aeeb9f
SHA512616a7ade5cfe4138d1f37590253512d4c9414fe4abf452bad00abc81912ba2a58474fd9689c1042e901d74804e07ce48b268391c2535a79783072819da41e1f6
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\ProgramData\mozglue.dllFilesize
133KB
MD58f73c08a9660691143661bf7332c3c27
SHA137fa65dd737c50fda710fdbde89e51374d0c204a
SHA2563fe6b1c54b8cf28f571e0c5d6636b4069a8ab00b4f11dd842cfec00691d0c9cd
SHA5120042ecf9b3571bb5eba2de893e8b2371df18f7c5a589f52ee66e4bfbaa15a5b8b7cc6a155792aaa8988528c27196896d5e82e1751c998bacea0d92395f66ad89
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\ProgramData\nss3.dllFilesize
1.2MB
MD5bfac4e3c5908856ba17d41edcd455a51
SHA18eec7e888767aa9e4cca8ff246eb2aacb9170428
SHA256e2935b5b28550d47dc971f456d6961f20d1633b4892998750140e0eaa9ae9d78
SHA5122565bab776c4d732ffb1f9b415992a4c65b81bcd644a9a1df1333a269e322925fc1df4f76913463296efd7c88ef194c3056de2f1ca1357d7b5fe5ff0da877a66
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\ProgramData\sqlite3.dllFilesize
630KB
MD5e477a96c8f2b18d6b5c27bde49c990bf
SHA1e980c9bf41330d1e5bd04556db4646a0210f7409
SHA25616574f51785b0e2fc29c2c61477eb47bb39f714829999511dc8952b43ab17660
SHA512335a86268e7c0e568b1c30981ec644e6cd332e66f96d2551b58a82515316693c1859d87b4f4b7310cf1ac386cee671580fdd999c3bcb23acf2c2282c01c8798c
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memory/468-79-0x0000000000400000-0x0000000000438000-memory.dmpFilesize
224KB
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memory/468-74-0x000000000040717B-mapping.dmp
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memory/468-85-0x0000000000400000-0x0000000000438000-memory.dmpFilesize
224KB
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memory/468-76-0x0000000000400000-0x0000000000438000-memory.dmpFilesize
224KB
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memory/468-73-0x0000000000400000-0x0000000000438000-memory.dmpFilesize
224KB
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memory/468-64-0x0000000000400000-0x0000000000438000-memory.dmpFilesize
224KB
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memory/468-65-0x0000000000400000-0x0000000000438000-memory.dmpFilesize
224KB
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memory/468-67-0x0000000000400000-0x0000000000438000-memory.dmpFilesize
224KB
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memory/468-69-0x0000000000400000-0x0000000000438000-memory.dmpFilesize
224KB
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memory/468-71-0x0000000000400000-0x0000000000438000-memory.dmpFilesize
224KB
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memory/680-86-0x0000000000000000-mapping.dmp
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memory/864-84-0x0000000000000000-mapping.dmp
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memory/1324-59-0x0000000000000000-mapping.dmp
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memory/1324-78-0x000000006E830000-0x000000006EDDB000-memory.dmpFilesize
5.7MB
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memory/1324-80-0x000000006E830000-0x000000006EDDB000-memory.dmpFilesize
5.7MB
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memory/1328-60-0x0000000000000000-mapping.dmp
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memory/2032-63-0x00000000043D0000-0x000000000440C000-memory.dmpFilesize
240KB
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memory/2032-58-0x000000000A220000-0x000000000A2A8000-memory.dmpFilesize
544KB
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memory/2032-54-0x0000000000EA0000-0x0000000000F5C000-memory.dmpFilesize
752KB
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memory/2032-57-0x0000000000910000-0x000000000091A000-memory.dmpFilesize
40KB
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memory/2032-56-0x00000000008B0000-0x00000000008C6000-memory.dmpFilesize
88KB
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memory/2032-55-0x0000000075A81000-0x0000000075A83000-memory.dmpFilesize
8KB