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

Static analysis result for SHA-256 2a6268b40dfcce76…

MALICIOUS

Office (OLE) / .XLSX

142.5 KB Created: 2010-02-10 09:32:00 Authoring application: Microsoft Excel
MD5: 4bfeea8b58b43a2904f0f96b8c402ea3 SHA-1: cea90f60ff4edf17a060b22f2d64c7bc2538c2c8 SHA-256: 2a6268b40dfcce76debad517ba11d8e619a948a9e35aa12ccd772f017105e9a6
220 Risk Score

Malware Insights

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

The sample contains critical heuristics indicating the presence of Excel 4.0 (XLM) macros, specifically an Auto_Open macro that utilizes dangerous formula APIs like RUN. The presence of 'XL4Poppy' in the document body and embedded artifacts further suggests a connection to this macro type. While the VBA macros are present, the primary execution mechanism appears to be the older XLM macro sheet, which is known for its ability to download and execute arbitrary code. The document body content, detailing personal information and benefit adjustments, serves as a lure to trick users into opening and enabling the macros.

Heuristics 5

  • 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.
  • Legacy Excel formula macro virus marker critical OLE_XLS_FORMULA_MACRO_VIRUS
    Workbook stream contains self-identifying legacy Excel formula macro virus markers. This indicates the document carries formula macro virus content even when no VBA project or modern XLM macro-sheet structure is present.
  • 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.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
2d6e4ad77eb1023b05b4250242bbbcc26a57b65388c934381fa54ed258be0bfb		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 152901 bytes
macros.bas
98b7a7ebcab0b44dbe1b6ee97261e584a38c75151ed5cb484a9b0cb4fbd55efb		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 5055 bytes

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