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

Static analysis result for SHA-256 e4acafbd7398f0a8…

MALICIOUS

Office (OLE) / .XLSX

31.0 KB Created: 2021-01-28 13:21:05 Authoring application: Microsoft Excel
MD5: 9bbb39167a454ff5fa8266c655ac39f3 SHA-1: 88aeef41ca4c21a4c3db646f5cb51f56f8ecd59b SHA-256: e4acafbd7398f0a81d07018b5023903b85dee460457ad11c1ceb950050caf80b
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an Excel 4.0 macro sheet (XLM) that contains an Auto_Open macro, which is a known technique for executing malicious code upon opening the document. The document body explicitly instructs the user to 'enable Editing and Content mode', serving as a lure to bypass security settings. The presence of the Auto_Open macro and the lure strongly suggest a malicious intent to execute further payloads, although the specific payload mechanism is not detailed in the extracted XLM macro content.

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
19a20a6749a35650aa1e254d75603354ab7b0c4f37b1bf19c0af0309631b8271
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3255 bytes