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

Static analysis result for SHA-256 c8d297ffe569ab6a…

MALICIOUS

Office (OLE) / .XLS

41.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 5e964b5079a6f0e7eb72d172a5fc643e SHA-1: 764825c8dbd1e8f0fb10f885963632061c5a363e SHA-256: c8d297ffe569ab6a29ebac9d1f4b2a515ac830dfb96d50c56ed79abdd2d3dbf1
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The critical heuristic OLE_XLM_AUTOOPEN_DEFINEDNAME indicates the presence of an Excel 4.0 Auto_Open macro. The OLE_XLM_DANGEROUS_FN heuristic further confirms that this macro uses dangerous functions, specifically 'RUN', which is commonly used to execute arbitrary commands. The presence of an Auto_Open macro strongly suggests an intent to automatically execute malicious code upon opening the spreadsheet, likely for initial payload delivery.

Heuristics 3

  • 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.
  • 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
b24cc29ccb155ade6613a3fe2ff54825039e723b2ec12e78fddd9f508fd67050
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8276 bytes