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

Static analysis result for SHA-256 ef4d2882e6b2e6b0…

MALICIOUS

Office (OLE) / .XLSX

234.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: e6d9faaa5ca0c3ec42b3f1917244a54f SHA-1: b1927b79079c679b8b0a90bf295cdb28f7608789 SHA-256: ef4d2882e6b2e6b0f6cb188f9302f53f0d42ceb0afed97cbc0e7f293f2741375
180 Risk Score

Malware Insights

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

The sample is an Excel 4.0 (XLM) macro-enabled spreadsheet. It contains an Auto_Open macro, which is a known technique for executing malicious code upon opening the document. The document body attempts to lure the user into enabling content by claiming it is protected. The XLM macro sheet contains a HALT gate, indicating environment evasion, and uses the RUN API, suggesting it attempts to execute external commands or payloads.

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
b76389af76ee732476cfd418371ac0f242ef803497d835fafcbdccb6101a8568		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 338033 bytes

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