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

Static analysis result for SHA-256 73952f15b752208f…

MALICIOUS

Office (OLE) / .XLS

31.0 KB Created: 2021-01-28 12:16:59 Authoring application: Microsoft Excel
MD5: db520ef2fb837449de0ca0cc1ba1a5f2 SHA-1: 8f61fe1f84721e43c3aa0d07f6a010ac999d375f SHA-256: 73952f15b752208fc79faf15880ba1e11b0487847dbc4985c67f0dec3aef647a
160 Risk Score

Malware Insights

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

The sample is an Excel 4.0 (XLM) macro-enabled spreadsheet. It contains an Auto_Open macro that uses dangerous formula APIs, specifically the RUN function. The document body instructs the user to enable editing and content, a common lure to bypass security measures and execute the macro. No specific family could be identified, but the technique is consistent with macro-based malware delivery.

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
7bc61fbb53502f39ab306c03b15f4f9f411b6a97c7a0867429defe4292af3ae1
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3495 bytes