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

Static analysis result for SHA-256 baa6456247affe4c…

MALICIOUS

Office (OLE) / .XLSX

142.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 6a85d925588c5b3267559b6191e96e68 SHA-1: 73b33ca7131e4d8503a52018ecc62166a53063aa SHA-256: baa6456247affe4c92ceb2199d484c7956401999d012567a6e1b9960a3036055
180 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros, specifically an Auto_Open macro, which is a known technique for executing malicious code upon opening the document. The heuristics indicate the use of dangerous formula APIs and environment evasion, suggesting an attempt to run arbitrary commands. The document body's text about enabling editing and content further supports the lure to execute the macro.

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.
  • XLM Auto_Open environment-evasion HALT gate high OLE_XLM_ENVIRONMENT_EVASION_HALT
    Excel 4.0 macro sheet auto-executes multiple GET.WORKSPACE / GET.WINDOW environment checks and halts execution when the host does not match the expected user environment. This is a common sandbox-evasion pattern in XLM malware and is stronger than a bare XLM macro-sheet indicator.
  • 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
6790721a025bf8c0e02e5e69bb9ecb75deb23181f03a5505461a8b9df3380ddf		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 171153 bytes

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