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

Static analysis result for SHA-256 c948a4a9a4891608…

MALICIOUS

Office (OLE) / .XLS

87.0 KB Created: 2020-05-26 20:41:43 Authoring application: Microsoft Excel
MD5: cdf851b6436a639b05d2b381fb177207 SHA-1: 23da03c26cce65a48797ae165971dae5f31d6e11 SHA-256: c948a4a9a4891608dd381e390756416b29d7d99bdb075374a86db6cff0194167
200 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that uses dangerous functions, specifically RUN. The macro sheet contains a reconstructed URL, 'http://gsag.dobruilcmneXCNvMPFkURLODwTAJSEKyvTZgLYXnrtlLaS', which is likely used to download and execute a second-stage payload. The presence of the RUN function and the embedded URL strongly suggests a downloader attack pattern.

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.
  • ClamAV: Xls.Dropper.Agent-7913400-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7913400-0
  • 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
c6704a905d4f3ef40322fbd2f8cfdaddf48d3f4d6d345d9da6560775b607ccbb		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 64395 bytes

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