Analysis

  • max time kernel
    120s
  • max time network
    121s
  • platform
    windows7_x64
  • resource
    win7v20210410
  • submitted
    06-05-2021 12:03

General

  • Target

    PO5621.scr.exe

  • Size

    306KB

  • MD5

    b0926a6e4c1887f81024b17df73199c5

  • SHA1

    3fcdd6ff8323713c8cf3e11edca6c5e195dd4139

  • SHA256

    244cc88debf6465b93584d1f63c592c52bd029deec2f24fc4a3328725838d239

  • SHA512

    b16dd1c26ce8c4654202a9ca779f3a2ce12a563a5b7670e06610829d2b1abd092543a524247ed7997d56f26bb1d02b5c6310eb12a5a741260ab298fb5d61f1f8

Malware Config

Extracted

Family

oski

C2

203.159.80.65

Signatures

  • Oski

    Oski is an infostealer targeting browser data, crypto wallets.

  • Downloads MZ/PE file
  • Deletes itself 1 IoCs
  • Loads dropped DLL 6 IoCs
  • Reads user/profile data of web browsers 2 TTPs

    Infostealers often target stored browser data, which can include saved credentials etc.

  • Accesses cryptocurrency files/wallets, possible credential harvesting 2 TTPs
  • Checks installed software on the system 1 TTPs

    Looks up Uninstall key entries in the registry to enumerate software on the system.

  • Suspicious use of SetThreadContext 1 IoCs
  • Enumerates physical storage devices 1 TTPs

    Attempts to interact with connected storage/optical drive(s). Likely ransomware behaviour.

  • Checks processor information in registry 2 TTPs 1 IoCs

    Processor information is often read in order to detect sandboxing environments.

  • Kills process with taskkill 1 IoCs
  • Suspicious behavior: MapViewOfSection 1 IoCs
  • Suspicious use of AdjustPrivilegeToken 1 IoCs
  • Suspicious use of WriteProcessMemory 13 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\PO5621.scr.exe
    "C:\Users\Admin\AppData\Local\Temp\PO5621.scr.exe"
    1⤵
    • Loads dropped DLL
    • Suspicious use of SetThreadContext
    • Suspicious behavior: MapViewOfSection
    • Suspicious use of WriteProcessMemory
    PID:1096
    • C:\Users\Admin\AppData\Local\Temp\PO5621.scr.exe
      "C:\Users\Admin\AppData\Local\Temp\PO5621.scr.exe"
      2⤵
      • Loads dropped DLL
      • Checks processor information in registry
      • Suspicious use of WriteProcessMemory
      PID:1200
      • C:\Windows\SysWOW64\cmd.exe
        "C:\Windows\System32\cmd.exe" /c taskkill /pid 1200 & erase C:\Users\Admin\AppData\Local\Temp\PO5621.scr.exe & RD /S /Q C:\\ProgramData\\546498067793251\\* & exit
        3⤵
        • Deletes itself
        • Suspicious use of WriteProcessMemory
        PID:1484
        • C:\Windows\SysWOW64\taskkill.exe
          taskkill /pid 1200
          4⤵
          • Kills process with taskkill
          • Suspicious use of AdjustPrivilegeToken
          PID:876

Network

MITRE ATT&CK Matrix ATT&CK v6

Credential Access

Credentials in Files

2
T1081

Discovery

Query Registry

2
T1012

System Information Discovery

2
T1082

Collection

Data from Local System

2
T1005

Replay Monitor

Loading Replay Monitor...

Downloads

  • \ProgramData\mozglue.dll
    MD5

    8f73c08a9660691143661bf7332c3c27

    SHA1

    37fa65dd737c50fda710fdbde89e51374d0c204a

    SHA256

    3fe6b1c54b8cf28f571e0c5d6636b4069a8ab00b4f11dd842cfec00691d0c9cd

    SHA512

    0042ecf9b3571bb5eba2de893e8b2371df18f7c5a589f52ee66e4bfbaa15a5b8b7cc6a155792aaa8988528c27196896d5e82e1751c998bacea0d92395f66ad89

  • \ProgramData\msvcp140.dll
    MD5

    109f0f02fd37c84bfc7508d4227d7ed5

    SHA1

    ef7420141bb15ac334d3964082361a460bfdb975

    SHA256

    334e69ac9367f708ce601a6f490ff227d6c20636da5222f148b25831d22e13d4

    SHA512

    46eb62b65817365c249b48863d894b4669e20fcb3992e747cd5c9fdd57968e1b2cf7418d1c9340a89865eadda362b8db51947eb4427412eb83b35994f932fd39

  • \ProgramData\nss3.dll
    MD5

    bfac4e3c5908856ba17d41edcd455a51

    SHA1

    8eec7e888767aa9e4cca8ff246eb2aacb9170428

    SHA256

    e2935b5b28550d47dc971f456d6961f20d1633b4892998750140e0eaa9ae9d78

    SHA512

    2565bab776c4d732ffb1f9b415992a4c65b81bcd644a9a1df1333a269e322925fc1df4f76913463296efd7c88ef194c3056de2f1ca1357d7b5fe5ff0da877a66

  • \ProgramData\sqlite3.dll
    MD5

    e477a96c8f2b18d6b5c27bde49c990bf

    SHA1

    e980c9bf41330d1e5bd04556db4646a0210f7409

    SHA256

    16574f51785b0e2fc29c2c61477eb47bb39f714829999511dc8952b43ab17660

    SHA512

    335a86268e7c0e568b1c30981ec644e6cd332e66f96d2551b58a82515316693c1859d87b4f4b7310cf1ac386cee671580fdd999c3bcb23acf2c2282c01c8798c

  • \ProgramData\vcruntime140.dll
    MD5

    7587bf9cb4147022cd5681b015183046

    SHA1

    f2106306a8f6f0da5afb7fc765cfa0757ad5a628

    SHA256

    c40bb03199a2054dabfc7a8e01d6098e91de7193619effbd0f142a7bf031c14d

    SHA512

    0b63e4979846ceba1b1ed8470432ea6aa18cca66b5f5322d17b14bc0dfa4b2ee09ca300a016e16a01db5123e4e022820698f46d9bad1078bd24675b4b181e91f

  • \Users\Admin\AppData\Local\Temp\nsc2FE7.tmp\9ma115elvnv.dll
    MD5

    8102c61b4698d608f7912b3979dc60a9

    SHA1

    48741a2b677d4214dce9dd7fdc8c09f0c71273e4

    SHA256

    b4e1b5a689c836a40a478137f6335f193f0eda0a90f8bd7868c6e7bc96f30fe3

    SHA512

    495be5aef1a63b6270aa0f92c68f13c21e16ef3ddd943507f66af25659dc1aa0b465d1e857af06f42fe05983b07ef1d3b0c96a7a595d84066517264d70640a8d

  • memory/876-72-0x0000000000000000-mapping.dmp
  • memory/1096-60-0x0000000075281000-0x0000000075283000-memory.dmp
    Filesize

    8KB

  • memory/1096-64-0x00000000003C0000-0x00000000003C2000-memory.dmp
    Filesize

    8KB

  • memory/1200-62-0x000000000040717B-mapping.dmp
  • memory/1200-65-0x0000000000400000-0x0000000000438000-memory.dmp
    Filesize

    224KB

  • memory/1484-71-0x0000000000000000-mapping.dmp