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

Static analysis result for SHA-256 480e24e75c71c5a6…

MALICIOUS

Office (OLE) / .XLSX

143.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 037e36c51a797ae4f55dd28cb71aa5ed SHA-1: 79f33d17bc250be80b2430944f8a8a23f7d4eb13 SHA-256: 480e24e75c71c5a6da53b4f334cd77b295fc778ed13062e23d201ff1189f3972
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File

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 document body displays a deceptive message claiming the document is encrypted and urging the user to 'Enable Editing' and 'Enable Content', a common social engineering tactic. The presence of the Auto_Open macro with dangerous formula APIs and environment evasion suggests it's designed to download and execute a secondary payload.

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
91c5aed55acda549c50b2da3526bc866ccd865b066bc40517dd18a2ae85ffc16		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 175373 bytes

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