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

Static analysis result for SHA-256 769ab14597f0fc0f…

MALICIOUS

Office (OLE) / .XLS

35.5 KB Created: 2021-02-16 08:10:08 Authoring application: Microsoft Excel
MD5: c2fe94c0a4b41acf21580425c9d6da5d SHA-1: 697b4675ef06283e5ce12ae52f123e76a5343b4e SHA-256: 769ab14597f0fc0fe701ff9caf7e2de93638928c6081dbd5612c2e130e416fd1
80 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The critical heuristic firing indicates the presence of an Excel 4.0 Auto_Open macro, which is designed to execute automatically when the workbook is opened. The macro sheet contains obfuscated code that appears to construct and execute commands, likely for downloading and running a secondary payload. The presence of an Auto_Open macro strongly suggests this file was delivered as a malicious attachment.

Heuristics 2

  • 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.
  • 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
72a2521161f5f043ede7d20767edab34d4011487ac1f15eca5eab28ddc2ce0d0		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 16389 bytes

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