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

Static analysis result for SHA-256 329c1c3b1d799550…

MALICIOUS

Office (OLE) / .XLS

46.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-08
MD5: 7b0861c5de55235e8e4efecde68f23ba SHA-1: 0daf3854343b073eed91107621cd5a5e8811681e SHA-256: 329c1c3b1d799550a827941cec64efe4e8d09e991faf76796da13917cc7a36d8
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open function, specifically using the RUN API. The extracted URLs are likely used to download and execute a second-stage payload. The macro's intent is to leverage the Auto_Open entry point to initiate the malicious chain.

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
f02d63843d495ffd8e99f1b7fe5f87a80501a758c9a61d8585f8be9700f36cb3		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7798 bytes

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