Resubmissions

10-04-2021 16:20

210410-3cqzjcbqw6 10

31-03-2021 11:29

210331-tzwgrtj9yx 7

Analysis

  • max time kernel
    124s
  • max time network
    122s
  • platform
    windows7_x64
  • resource
    win7v20201028
  • submitted
    10-04-2021 16:20

General

  • Target

    Document_Opener.exe.14.dr.exe

  • Size

    1.4MB

  • MD5

    4d182167da3f24bfb9e80469b0d7d62a

  • SHA1

    1bb377017690bd7066bb98658a8bb90d91feeb93

  • SHA256

    e0fb60da371912c158861c9660632d58e45cfcff12351cc9e03f497f319eb5de

  • SHA512

    1ea73e9857320cf1571ffef0ec8ce042ff708c2ab8b8cde890f6afe3f82ac2e8106a2539d729f7e018ae0e82eb364eca3a0bea5f6acc919855574cbac2784302

Score
10/10

Malware Config

Extracted

Family

rustybuer

C2

https://gestahibanking.com/

Signatures

  • RustyBuer

    RustyBuer is a new variant of Buer loader written in Rust.

  • Loads dropped DLL 1 IoCs
  • Enumerates connected drives 3 TTPs 49 IoCs

    Attempts to read the root path of hard drives other than the default C: drive.

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

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

  • Program crash 1 IoCs
  • Suspicious behavior: EnumeratesProcesses 5 IoCs
  • Suspicious behavior: GetForegroundWindowSpam 1 IoCs
  • Suspicious behavior: MapViewOfSection 1 IoCs
  • Suspicious use of AdjustPrivilegeToken 1 IoCs
  • Suspicious use of WriteProcessMemory 9 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\Document_Opener.exe.14.dr.exe
    "C:\Users\Admin\AppData\Local\Temp\Document_Opener.exe.14.dr.exe"
    1⤵
    • Loads dropped DLL
    • Suspicious use of SetThreadContext
    • Suspicious behavior: MapViewOfSection
    • Suspicious use of WriteProcessMemory
    PID:1716
    • C:\Users\Admin\AppData\Local\Temp\Document_Opener.exe.14.dr.exe
      "C:\Users\Admin\AppData\Local\Temp\Document_Opener.exe.14.dr.exe"
      2⤵
      • Enumerates connected drives
      • Suspicious use of WriteProcessMemory
      PID:1156
      • C:\Windows\SysWOW64\WerFault.exe
        C:\Windows\SysWOW64\WerFault.exe -u -p 1156 -s 440
        3⤵
        • Program crash
        • Suspicious behavior: EnumeratesProcesses
        • Suspicious behavior: GetForegroundWindowSpam
        • Suspicious use of AdjustPrivilegeToken
        PID:1668

Network

MITRE ATT&CK Enterprise v6

Replay Monitor

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Downloads

  • memory/1156-63-0x0000000000400000-0x0000000000534000-memory.dmp

    Filesize

    1.2MB

  • memory/1668-65-0x00000000003E0000-0x00000000003E1000-memory.dmp

    Filesize

    4KB

  • memory/1716-60-0x00000000766F1000-0x00000000766F3000-memory.dmp

    Filesize

    8KB