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

Static analysis result for SHA-256 65551b81a1eaaee7…

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-25 10:47:04 Authoring application: Microsoft Excel
MD5: 68f8c153753a2ce0777673bceebc319a SHA-1: 5680653da2d1c439b6522bb67fb3190b56df7082 SHA-256: 65551b81a1eaaee72cb911a565e6bdea56d572fbc5c1d8ca07a0831f9216551e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. The presence of dangerous formula APIs like RUN indicates that the macro is designed to perform actions beyond standard spreadsheet operations. While no specific URLs or hashes were extracted, the Auto_Open macro itself is the primary indicator of malicious intent, likely serving as a loader for further malicious activity.

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
11aed356fb66033b47319e74f6838f7bbb9b2f079ef75f71a3de04a0767f14d5
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6494 bytes