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

Static analysis result for SHA-256 d1396807bb1afb68…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:44:09 Authoring application: Microsoft Excel
MD5: 6ab00f07fdf11c49fd6de8086bf487fd SHA-1: e41091deca3a167b0e715b07a5742bef834cf53a SHA-256: d1396807bb1afb68b3679663b6ac751cb4c1ee16dda729b7365d04fd53f2749e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The sample contains Excel 4.0 (XLM) macro sheets, specifically triggering critical heuristics for OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN. The presence of an 'Auto_Open' defined name indicates that the macro will execute automatically upon opening the workbook. The dangerous formula APIs, including 'RUN=0', suggest the macro is designed to execute arbitrary commands or download and run a secondary payload. The document body contains obfuscated text, further supporting a malicious intent.

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
9ecfe37a3aa050aec1da4c450d76ed7dba1d2a45304a0f201c8e9c35260f8a71
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6552 bytes