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

Static analysis result for SHA-256 b604bdaca6ab10ea…

MALICIOUS

Office (OLE) / .XLS

695.5 KB Created: 2009-01-07 05:08:55 Authoring application: Microsoft Excel
MD5: 0f5e87e5bd64f9bd46a1944f3fba003f SHA-1: c8e64f0fe309632fa6ee2edf5aa77d53fefda438 SHA-256: b604bdaca6ab10eadb8493068803b36065e46eb43357e97f052e32a239e7aa85
240 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell T1566.001 Spearphishing Attachment

The sample is an Excel 4.0 spreadsheet containing a hidden macro sheet with an Auto_Open entry. Heuristics indicate the use of dangerous functions like RUN, and legacy macro-virus markers such as XL4Poppy and Normal_MacroVirus. The macro sheet contains comments indicating it copies infected files and is a destructive virus. The document body presents a fabricated expense report to disguise the malicious intent.

Heuristics 4

  • Excel 4.0 (XLM) Auto_Open + macro sheet critical OLE_XLM_AUTOOPEN
    Workbook contains an Auto_Open / Auto_Close defined name together with an Excel 4.0 macro sheet — the canonical XLM auto-execution shape used by malware families such as Emotet and QakBot.
  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • Legacy XLM macro-virus family marker critical OLE_XLM_LEGACY_MACRO_VIRUS
    Workbook contains an Excel 4.0 macro Auto_Open chain and legacy macro-virus family strings. This is a narrow indicator for infected XLM workbooks rather than ordinary formula use.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
99f14574c1c9ea88c49f8f0b76ce0c2e3b01a88d56ff44850f4eaeb8b45e0924		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 180580 bytes

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