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

Static analysis result for SHA-256 1b4af704fb5af49f…

MALICIOUS

Office (OLE) / .XLSX

106.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2022-05-31
MD5: b01c11f1da2f1e5c64d90b0273e4cadd SHA-1: a8f0abaf0167de16380a1a515d0aa16288f27338 SHA-256: 1b4af704fb5af49f4a05a2721e9255621406d10ae9d6dea4835100c7e46f09e7
120 Risk Score

Malware Insights

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

The presence of Excel 4.0 macros, specifically an Auto_Open defined name, indicates that the document is designed to execute code upon opening. The document body and macro sheet metadata suggest a lure to impersonate DocuSign, instructing the user to enable macros. The extracted URLs are likely destinations for downloading a second-stage payload, and the presence of 'rundll32.exe' with 'DllRegisterServer' suggests a component of the payload execution.

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
404f0e01d629b2f4d86e1affb27c10c9f07baccb002a01d7ecaf0166ee6b100f
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3765 bytes