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

Static analysis result for SHA-256 108f3f1eeead9c1f…

MALICIOUS

Office (OLE) / .XLS

65.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-24
MD5: 4fbbfa577162c82907d6798ad48c4f0e SHA-1: 559fa34a6e41607792a1a19973db08ec4a31543c SHA-256: 108f3f1eeead9c1f8d1df4ed429f7133dfedcbe58dad3d9000c18945455d819f
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open entry, which is a critical finding. The macros construct and attempt to access multiple URLs, indicating a likely downloader or initial access mechanism. The concatenated URLs are reconstructed as "http://newkano.com/wp-admin/66rIsrVwoPKUsjcAs/", "http://ocaloogulari.com/inc/Wcm82enrs8/", "https://myphamcuatui.com/assets/OPVeVSpO/", and "http://sieuhiphutun gxengan.com/old_source/9boJQZpTSdQe/". This behavior strongly suggests the file is designed to download and execute a secondary payload.

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
67f6b164c4d6ea1ea8efe2ccdff056dde7fd1072da2bb20afe3b275864086c71		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7678 bytes

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