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

Static analysis result for SHA-256 4b179d5e82aaefe1…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:36:04 Authoring application: Microsoft Excel
MD5: 803a84622f34ff42c144c102a1e2c521 SHA-1: 0fb9aaded0ff32dbb9b4a27833b25192124ffe20 SHA-256: 4b179d5e82aaefe1fd178685c46537327693ade72cbd7a1c35d719ae586dd5ff
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a known technique for executing malicious code upon opening the workbook. The critical heuristic firings indicate the presence of dangerous formula APIs like RUN=0, suggesting the macro is designed to execute arbitrary commands. No specific IOCs like URLs or hashes were extracted, but the Auto_Open technique itself is a high-priority indicator.

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.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
d471c19d287bf082dd90f2480a36e88a6be53c0f878a5fd4e66645cf758b491a
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6508 bytes