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

Static analysis result for SHA-256 56fb787c0fa00249…

MALICIOUS

Office (OOXML) / .XLSM

412.5 KB Authoring application: Microsoft Excel 16.0300 First seen: 2022-08-11
MD5: 12104e63b3913da5445eca8b290a1d0f SHA-1: e371e91fa8ab97187d1c7f8dd034ce04374de0d8 SHA-256: 56fb787c0fa00249b0779426e958135a6951ea90203a9de026b714c6a0478776
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.002 Spearphishing Attachment T1059.005 Visual Basic

The Workbook_Open macro is obfuscated and uses CreateObject to execute a PowerShell command. This command downloads a file named 'v.exe' from 'http://my-v-file.syno-ds.de/v.exe' and saves it as 'C:\Users\Public\picff.exe', then executes it. This indicates a downloader or droppper functionality.

Heuristics 7

  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open 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.
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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 http://my-v-file.syno-ds.de/v.exe

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
cd265151ce0e9a183b634dc578e8c816f9d89bdc5635ee2168b0ade48818e747		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1629 bytes
vbaProject_00.bin
63d0c65b782781ba00f11d15182bdff6c7917a4dc6cf2c25e893a09ef43166c0		 vba-project OOXML VBA project: xl/vbaProject.bin 16896 bytes

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