Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 7cf7b8e58c595569…

MALICIOUS

Office (OOXML) / .XLSM

56.6 KB Created: 2022-06-25 19:05:11 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-11-10
MD5: 8627921983baab8f93b6150dd57f16a5 SHA-1: 4d17d0b708cb3545da5473b12be81d5942e8c757 SHA-256: 7cf7b8e58c5955697c7de6b8d90936ba16fde52e1004c5854ad5b2a731b8a7b0
322 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.003 Windows Command Shell T1105 Ingress Tool Transfer T1204.002 Malicious File

The VBA macro within the Excel file utilizes `CreateObject("WScript.Shell")` and `Shell()` to download a DLL payload from the hardcoded URL `https://irs.reviews/KFOJRIOHNV(R)(A#IFK)_FIO#)_FK_D/0411r_cr4.dll`. The script then saves this payload to the user's My Documents folder as `name.dll`, indicating a downloader functionality. The presence of an `auto_close` macro further suggests an automated execution upon document interaction.

Heuristics 8

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://irs.reviews/KFOJRIOHNV(R)(A#IFK)_FIO#)_FK_D/0411r_cr4.dll

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
7ffc6e0aba57e744c2bbb8070bef9ded08ed96406272b0558348bc9575dda075		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 3594 bytes
vbaProject_00.bin
ecf57803437ee01ebb95b0a3c4e57e245c2168ef6d0e2fbc8ae094fc44a91552		 vba-project OOXML VBA project: xl/vbaProject.bin 22528 bytes

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