Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 28b9c2dc30ff9b5f…

MALICIOUS

Office (OLE) / .XLSX

40.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel First seen: 2022-07-07
MD5: c3b09892a6e17b708ef703e0f9a5c4f1 SHA-1: 2d90b2d0dae6f4f5c322f250fdcd6a3afb2a519e SHA-256: 28b9c2dc30ff9b5f7a4f8bc6daba540dbeeb28351e3f826b9388a45458e02bfc
342 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.003 Windows Command Shell T1218.011 System Binary Proxy Execution: Rundll32

The Workbook_Open macro is obfuscated and uses GetObject to execute a command. The reconstructed command string 'Wscript.Shell' indicates the intent to run a script or executable. The presence of mshta.exe references and the general structure suggest a downloader or initial access mechanism. The URL points to a benign file, but the macro's behavior is malicious.

Heuristics 9

  • 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.
  • ClamAV: Xls.Malware.Valyria-10002968-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Valyria-10002968-0
  • Reference to mshta.exe high SC_STR_MSHTA
    Reference to mshta.exe
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject 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 macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • 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://www.mediafire.com/file/au4vgvrfmmfj7ka/23.htm/file

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
674876e8efefe1ee7cc488cba75e85cfd0d1d1f757b429e168657ad0351ae6bc		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1502 bytes

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