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

Static analysis result for SHA-256 09fc0b5eb1be3550…

MALICIOUS

Office (OLE) / .XLSX

235.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 33e27ff9660aad36a2114748b740f5a4 SHA-1: fc2e7f670b27ab04743da1771eb496fccdb93bc9 SHA-256: 09fc0b5eb1be3550a1c9ca31f46bf4954190980b85a85fe5baeade6d08b330da
180 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, indicated by multiple critical heuristic firings including OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN. The document body presents a deceptive message about encryption, prompting the user to 'Enable Editing' and 'Enable Content', which is a common lure for macro-based malware. The presence of an Auto_Open macro suggests an attempt to automatically execute malicious code upon opening the document.

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
88721663838a989834588ae71e3c4ff6ccf0be4d7b6d4762999f5c21b3f6081b		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 332851 bytes

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