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

Static analysis result for SHA-256 1cda4d7b5f707e0a…

MALICIOUS

Office (OLE) / .XLSX

70.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-27
MD5: 5ea69683d7e3d0fd3a35bba0816b745a SHA-1: d435d37fdab9bc1e30261e14d274d4f44ad8b282 SHA-256: 1cda4d7b5f707e0a1dc12d16151cff7b6f8d5606db7bc4a760cf10b2444b6ec8
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. This macro is designed to execute a sequence of URLs, including "https://natayakim.com/_hlam/Ob78p6SxMNonofG/", "http://weplug.com/dom/LfdeV8H4Zy1yLFRV/", "http://martinmichalek.com/_sub/G1QKwEYPbt/", and "https://winkelsupply.nl/cgi-bin/ykyyGQC6UIXrEtCt37/". This behavior strongly suggests the macro's purpose is to download and execute a secondary stage payload from these remote locations.

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
699e21f010c7c5f5713063f52e691ec519f766e81393f8793f7a585cd43d5349		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7635 bytes

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