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

Static analysis result for SHA-256 490cb5121a4ce076…

MALICIOUS

Office (OLE) / .XLS

136.5 KB Created: 2019-10-22 07:10:34 Authoring application: Microsoft Excel
MD5: 3b41c3d33589de59952989dafd18f0a7 SHA-1: c37dc779c64fdad0a1c7e79de2ca7d26c754e0c2 SHA-256: 490cb5121a4ce0761111fe088bccdc6de5ce78ff082a356a4a39ee169b428491
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The sample is an Excel 4.0 spreadsheet containing an Auto_Open macro. This macro uses the EXEC function to run a PowerShell command, which is constructed by concatenating strings to form 'powershell -Command '. The PowerShell command then downloads content from 'http://paste.ee/r/v5e8E' and executes it. This indicates a downloader pattern designed to fetch and run a second-stage payload.

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.
  • Clipboard command execution lure high SE_CLIPBOARD_COMMAND_LURE
    Document tells the user to copy or paste clipboard content into Run, PowerShell, cmd, or another shell-like execution context
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
a0351851a6c49597445f17e7663f281591fb56ccbbecbd64563de4ea9cf00b06
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1070 bytes