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

Static analysis result for SHA-256 39ffaf6fffae3057…

MALICIOUS

Office (OLE) / .XLSX

274.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2022-09-22
MD5: 12a15bb618e039db7f49040998257fd9 SHA-1: 0d8bfab5e9c4424d2cd9e1ffb10568cd185c234f SHA-256: 39ffaf6fffae305719541ae64b4bdcbe504068bdebdc6496f1a9fa2b02c37f20
120 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros, including an Auto_Open entry, which are designed to execute automatically when the workbook is opened. The document body contains a lure impersonating a document signing service and instructs the user to enable macros. The embedded URL 'https://parkisolutions.com/nerugin.dll' is likely the location of a second-stage payload.

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.
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • Document signing service impersonation lure medium SE_DOCUSIGN_LURE
    Document impersonates DocuSign, Adobe Sign, or a similar signing service in a signing-request context

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
84db8022cd9373e19b3b88e0e3e8c161c0d41468768a7f50d479104c806845c5
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3274 bytes