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

Static analysis result for SHA-256 3cd2b72f85d145e8…

MALICIOUS

Office (OLE) / .XLSX

274.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 219a612b8cf85f5fecbb7e6e27ae0e47 SHA-1: a846e68a6d927ec6ea41b0958c20f02fed066842 SHA-256: 3cd2b72f85d145e8bfc5fadc184e97d6d102e3b22a45815358c43538c9c1dc18
120 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros, including an Auto_Open entry, which is a strong indicator of malicious intent. The document body and heuristics suggest a lure to enable macros by impersonating a document signing service. The extracted URL 'https://parkisolutions.com/nerugin.dll' and the command 'rundll32.exe C:\iofjgjfldnd.hde' indicate that the macro is likely designed to download and execute a second-stage 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