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

Static analysis result for SHA-256 524de4a84f503918…

MALICIOUS

Office (OLE) / .XLSX

31.0 KB Created: 2021-01-25 16:13:38 Authoring application: Microsoft Excel
MD5: c3b9fb6ca422802c3af00cb464ad5a26 SHA-1: 2a9be240a1503cb2f65371d01a3a241a95db75d5 SHA-256: 524de4a84f503918d4802a291bdc272d126e1b68f1d0c48fe93bf84a4e19d969
160 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File

The sample is an Excel file containing Excel 4.0 macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics. The DOC BODY explicitly instructs the user to 'enable Editing and Content mode', a common lure for macro execution. The presence of the RUN function within the XLM macro suggests it is designed to execute arbitrary commands or download further payloads.

Heuristics 4

  • 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.
  • 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
a46eb27d03742c2c8a177314f753eca269a329fc2459862ae170519572858b63
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3504 bytes