Analysis
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max time kernel
119s -
max time network
119s -
platform
windows10_x64 -
resource
win10v20210408 -
submitted
21-04-2021 13:30
Static task
static1
Behavioral task
behavioral1
Sample
gunzipped.exe
Resource
win7v20210408
Behavioral task
behavioral2
Sample
gunzipped.exe
Resource
win10v20210408
General
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Target
gunzipped.exe
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Size
212KB
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MD5
e8caac54776eac6e3740c9c8426486df
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SHA1
d6720055a125da5922be71b69b3a4078a49642ea
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SHA256
d75c69a49a30595964989b72499ec0e303ff42a0e2a334dda22a9cd9fd7e8ba5
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SHA512
0e16cb730971d507c9767b953c2d320b9b5a8099b736bcb42e92435d13cf77083ad2a98bf23a42af53c36907c29949f30f4e1e548662a76adb877487549f5bea
Malware Config
Extracted
guloader
https://drive.google.com/uc?export=download&id=1DEqX44va5nubrzi4f1gvY6qVc29IgPxG
Extracted
oski
45.85.90.86
Signatures
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Guloader,Cloudeye
A shellcode based downloader first seen in 2020.
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Oski
Oski is an infostealer targeting browser data, crypto wallets.
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Guloader Payload 3 IoCs
Processes:
resource yara_rule behavioral2/memory/564-116-0x00000000022B0000-0x00000000022BD000-memory.dmp family_guloader behavioral2/memory/200-117-0x0000000000401FBC-mapping.dmp family_guloader behavioral2/memory/200-120-0x0000000000560000-0x0000000000660000-memory.dmp family_guloader -
Downloads MZ/PE file
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Checks QEMU agent file 2 TTPs 2 IoCs
Checks presence of QEMU agent, possibly to detect virtualization.
Processes:
gunzipped.exegunzipped.exedescription ioc process File opened (read-only) C:\Program Files\Qemu-ga\qemu-ga.exe gunzipped.exe File opened (read-only) C:\Program Files\Qemu-ga\qemu-ga.exe gunzipped.exe -
Loads dropped DLL 3 IoCs
Processes:
gunzipped.exepid process 200 gunzipped.exe 200 gunzipped.exe 200 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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Legitimate hosting services abused for malware hosting/C2 1 TTPs
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Suspicious use of NtSetInformationThreadHideFromDebugger 3 IoCs
Processes:
gunzipped.exegunzipped.exepid process 564 gunzipped.exe 200 gunzipped.exe 200 gunzipped.exe -
Suspicious use of SetThreadContext 1 IoCs
Processes:
gunzipped.exedescription pid process target process PID 564 set thread context of 200 564 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 -
Kills process with taskkill 1 IoCs
Processes:
taskkill.exepid process 1596 taskkill.exe -
Suspicious behavior: MapViewOfSection 1 IoCs
Processes:
gunzipped.exepid process 564 gunzipped.exe -
Suspicious use of AdjustPrivilegeToken 1 IoCs
Processes:
taskkill.exedescription pid process Token: SeDebugPrivilege 1596 taskkill.exe -
Suspicious use of SetWindowsHookEx 1 IoCs
Processes:
gunzipped.exepid process 564 gunzipped.exe -
Suspicious use of WriteProcessMemory 10 IoCs
Processes:
gunzipped.exegunzipped.execmd.exedescription pid process target process PID 564 wrote to memory of 200 564 gunzipped.exe gunzipped.exe PID 564 wrote to memory of 200 564 gunzipped.exe gunzipped.exe PID 564 wrote to memory of 200 564 gunzipped.exe gunzipped.exe PID 564 wrote to memory of 200 564 gunzipped.exe gunzipped.exe PID 200 wrote to memory of 1504 200 gunzipped.exe cmd.exe PID 200 wrote to memory of 1504 200 gunzipped.exe cmd.exe PID 200 wrote to memory of 1504 200 gunzipped.exe cmd.exe PID 1504 wrote to memory of 1596 1504 cmd.exe taskkill.exe PID 1504 wrote to memory of 1596 1504 cmd.exe taskkill.exe PID 1504 wrote to memory of 1596 1504 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⤵
- Checks QEMU agent file
- Suspicious use of NtSetInformationThreadHideFromDebugger
- Suspicious use of SetThreadContext
- Suspicious behavior: MapViewOfSection
- Suspicious use of SetWindowsHookEx
- Suspicious use of WriteProcessMemory
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C:\Users\Admin\AppData\Local\Temp\gunzipped.exe"C:\Users\Admin\AppData\Local\Temp\gunzipped.exe"2⤵
- Checks QEMU agent file
- Loads dropped DLL
- Suspicious use of NtSetInformationThreadHideFromDebugger
- 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 200 & erase C:\Users\Admin\AppData\Local\Temp\gunzipped.exe & RD /S /Q C:\\ProgramData\\881028464230658\\* & exit3⤵
- Suspicious use of WriteProcessMemory
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C:\Windows\SysWOW64\taskkill.exetaskkill /pid 2004⤵
- Kills process with taskkill
- Suspicious use of AdjustPrivilegeToken
Network
MITRE ATT&CK Matrix ATT&CK v6
Replay Monitor
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Downloads
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\ProgramData\mozglue.dllMD5
8f73c08a9660691143661bf7332c3c27
SHA137fa65dd737c50fda710fdbde89e51374d0c204a
SHA2563fe6b1c54b8cf28f571e0c5d6636b4069a8ab00b4f11dd842cfec00691d0c9cd
SHA5120042ecf9b3571bb5eba2de893e8b2371df18f7c5a589f52ee66e4bfbaa15a5b8b7cc6a155792aaa8988528c27196896d5e82e1751c998bacea0d92395f66ad89
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\ProgramData\nss3.dllMD5
bfac4e3c5908856ba17d41edcd455a51
SHA18eec7e888767aa9e4cca8ff246eb2aacb9170428
SHA256e2935b5b28550d47dc971f456d6961f20d1633b4892998750140e0eaa9ae9d78
SHA5122565bab776c4d732ffb1f9b415992a4c65b81bcd644a9a1df1333a269e322925fc1df4f76913463296efd7c88ef194c3056de2f1ca1357d7b5fe5ff0da877a66
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\ProgramData\sqlite3.dllMD5
e477a96c8f2b18d6b5c27bde49c990bf
SHA1e980c9bf41330d1e5bd04556db4646a0210f7409
SHA25616574f51785b0e2fc29c2c61477eb47bb39f714829999511dc8952b43ab17660
SHA512335a86268e7c0e568b1c30981ec644e6cd332e66f96d2551b58a82515316693c1859d87b4f4b7310cf1ac386cee671580fdd999c3bcb23acf2c2282c01c8798c
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memory/200-117-0x0000000000401FBC-mapping.dmp
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memory/200-118-0x0000000000400000-0x0000000000553000-memory.dmpFilesize
1.3MB
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memory/200-119-0x0000000000401000-0x00000000004FD000-memory.dmpFilesize
1008KB
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memory/200-120-0x0000000000560000-0x0000000000660000-memory.dmpFilesize
1024KB
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memory/200-121-0x0000000000401000-0x0000000000541000-memory.dmpFilesize
1.2MB
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memory/200-122-0x0000000000400000-0x0000000000438000-memory.dmpFilesize
224KB
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memory/564-116-0x00000000022B0000-0x00000000022BD000-memory.dmpFilesize
52KB
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memory/1504-126-0x0000000000000000-mapping.dmp
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memory/1596-127-0x0000000000000000-mapping.dmp