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

Static analysis result for SHA-256 aed59f75bebfe497…

MALICIOUS

Office (OLE) / .XLS

81.5 KB Created: 2020-05-26 20:41:43 Authoring application: Microsoft Excel
MD5: 4941754b6f0a1e17034a79370231a9bb SHA-1: 1d14c63ffb807df83b329306852cf23fa28eb401 SHA-256: aed59f75bebfe49745b10d6a62e79325da10954117afa592c5e2c2fcad4898a2
200 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. The macros utilize dangerous formula APIs like RUN, indicating an intent to execute arbitrary code. The reconstructed URL 'http://gsa.dobruilcmne.cx/NZvMV' strongly suggests that this macro is designed to download and execute a second-stage payload. ClamAV also identified this as a dropper.

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-7902905-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7902905-0
  • 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
52610a4e1dde258eb5a366b0d67c3ff0135a8ac96957d094bbb6516197a3279a		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 53072 bytes

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