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

Static analysis result for SHA-256 860bc7f85116879f…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:38:28 Authoring application: Microsoft Excel
MD5: 1867a12175c10d81bfe5611298b587e0 SHA-1: 162e3310f7b6f951a166b41711a0fd39b21618aa SHA-256: 860bc7f85116879f04beff41622893d97eeac86cfbd85f5a37ce5088a81819a4
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1566.001 Spearphishing Attachment

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary commands. While the exact payload is not visible, the Auto_Open function strongly implies the macro's purpose is to download and execute a second-stage payload upon opening the document. No specific family could be identified.

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
a8bfa43adb506cf1ecebeb5bf8627c0a4fc9c29d0c6ef526863d49446f0932de
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6867 bytes