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

Static analysis result for SHA-256 a13cfb44603e3b71…

MALICIOUS

Office (OLE) / .XLSX

31.0 KB Created: 2021-01-28 13:40:40 Authoring application: Microsoft Excel
MD5: c2b4526d2a85fdf79b54ad5e391ce4cb SHA-1: 09ed33e5c6278af16c3afa20754dddb90c015248 SHA-256: a13cfb44603e3b71b3b3f8f081b78d27e89f18409c73e0d8dbfa2cb8b2565662
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.005 Visual Basic T1059.001 PowerShell

The sample is an Excel 4.0 macro-enabled spreadsheet. It contains an Auto_Open macro that uses dangerous functions, specifically the RUN function, indicating it is designed to execute arbitrary commands. The document body explicitly instructs the user to 'Enable Editing' and 'Enable Content', a common social engineering tactic to bypass macro security. No specific malware family could be identified, but the technique suggests a downloader or initial access 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.
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
5d1aaf953b58bf32a471d65f3f6a8c47f267bab15199ad3bcab8dd0a295038b1
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3357 bytes