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

Static analysis result for SHA-256 999799ddcef853bf…

MALICIOUS

Office (OLE) / .XLSX

31.0 KB Created: 2021-02-05 13:25:45 Authoring application: Microsoft Excel
MD5: e376b39131f03b1fecb3fb6c63543da3 SHA-1: e9d6241d93c680400fa4d9716ee9f36ac74be178 SHA-256: 999799ddcef853bf07800d3c7db17b3904936b0cea20ea6d9491000fd732b0d6
160 Risk Score

Malware Insights

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

The sample contains an Excel 4.0 macro sheet with an Auto_Open entry, indicating it will execute automatically when the workbook is opened. The document body explicitly instructs the user to 'Enable Editing' and 'Enable Content', a common social engineering tactic to bypass security measures. The presence of the 'RUN' function in the XLM macro further 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
f6b612420a6fb0d48f7ea5e12e1767d5f4f969f92bea229b1ec758e155876718
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3355 bytes