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

Static analysis result for SHA-256 64cecc966eb125b5…

MALICIOUS

Office (OLE) / .XLSX

274.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2022-09-22
MD5: 0082dcbd67a40d0217e988759c14d6cd SHA-1: 04c85dfd994691d9209d2004dc9bf6dc53c905aa SHA-256: 64cecc966eb125b52085b1d928b8ba0b33651ee927de1ca45c942e15f23691c0
120 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros with an Auto_Open entry, indicating automatic execution upon opening. It also includes a lure to enable macros by impersonating a document signing service. The embedded DOC BODY contains a URL, 'https://parkisolutions.com/nerugin.dll', and references to 'rundll32', suggesting the macro's purpose is to download and execute a DLL payload from the provided URL.

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