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

Static analysis result for SHA-256 348d709ab212ddbd…

MALICIOUS

Office (OLE) / .XLSX

327.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-20
MD5: 6fa95c9fc12894519b4332e029f564db SHA-1: a2c790235552eada56b639340edaa385b12862f4 SHA-256: 348d709ab212ddbd34fdcae6d27e7f1fb51569f3cb6d817889273682290a2f3b
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File T1059.001 PowerShell

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN indicate the presence of an Excel 4.0 Auto_Open macro. The macro concatenates strings to form URLs, which are then likely used to download a second-stage payload. The reconstructed URLs are: https://uniross.site/SvmGtFWNWs/I.png, https://alexadrivingschool.online/ViaawNbw/I.png, and https://adboat.live/TCA1oiqkA/I.png. This indicates a macro-based downloader attack.

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
4ce2eca84e77657cf47cd88188d1109ed7a2a5940734c07a9d94627fa54370cf		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7149 bytes

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