Analysis

  • max time kernel
    15s
  • max time network
    112s
  • platform
    windows10_x64
  • resource
    win10v20210408
  • submitted
    21-07-2021 16:19

General

  • Target

    6f9d943f88f715ff8a122d7b88af986c1a9f38f4484e48cde768cf22a5935efe.dll

Score
10/10

Malware Config

Extracted

Family

rustybuer

C2

https://shipmentofficedepot.com/

Signatures

  • RustyBuer

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

  • Blocklisted process makes network request 1 IoCs
  • Downloads MZ/PE file
  • Executes dropped EXE 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 WriteProcessMemory 6 IoCs

Processes

  • C:\Windows\system32\rundll32.exe
    rundll32.exe C:\Users\Admin\AppData\Local\Temp\6f9d943f88f715ff8a122d7b88af986c1a9f38f4484e48cde768cf22a5935efe.dll,#1
    1⤵
    • Suspicious use of WriteProcessMemory
    PID:632
    • C:\Windows\SysWOW64\rundll32.exe
      rundll32.exe C:\Users\Admin\AppData\Local\Temp\6f9d943f88f715ff8a122d7b88af986c1a9f38f4484e48cde768cf22a5935efe.dll,#1
      2⤵
      • Blocklisted process makes network request
      • Suspicious use of WriteProcessMemory
      PID:1264
      • C:\Users\Public\srtherhaeth.eXe
        C:\Users\Public\srtherhaeth.eXe
        3⤵
        • Executes dropped EXE
        • Enumerates connected drives
        PID:496

Network

MITRE ATT&CK Enterprise v6

Replay Monitor

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Downloads

  • memory/496-118-0x00000000006E0000-0x000000000082A000-memory.dmp

    Filesize

    1.3MB

  • memory/496-119-0x00000000026B0000-0x0000000002816000-memory.dmp

    Filesize

    1.4MB