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

Static analysis result for SHA-256 032fda43e5102e80…

MALICIOUS

Office (OLE) / .XLS

36.0 KB Created: 2020-11-27 11:41:30 Authoring application: Microsoft Excel First seen: 2022-04-24
MD5: 6608aff6b991ad32825ff725613f7dbe SHA-1: 8745557c0add27d7e0f197ee1f97c9ce8178bb06 SHA-256: 032fda43e5102e80073724e13022807a4f6a5af6400bb289c157923e4c9a6163
140 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing Excel 4.0 (XLM) macros, specifically an Auto_Open function. This function is known to be used for executing arbitrary code upon opening the document. The presence of dangerous formula APIs like RUN further indicates malicious intent, likely to download and execute a second-stage payload.

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
5fa5c899d9232ffbb6feb182607bea761a7eadbcf2c11afc9a8dc42f9639a1c5		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6792 bytes

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