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

Static analysis result for SHA-256 38632ed3b553f518…

MALICIOUS

Office (OLE) / .XLSX

105.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2022-05-31
MD5: d2e529ebfdb73f07d430ee6ed5f19a9b SHA-1: a4eb977169799d7f3110820f0a4fe9c25692ab2e SHA-256: 38632ed3b553f5183a8def4212b68f3c2bc793603cc3b1e41b533357d95caaaf
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 with an Auto_Open entry, indicating it will execute automatically when the document is opened. The 'SE_ENABLE_LURE' and 'SE_DOCUSIGN_LURE' heuristics confirm that the document attempts to trick the user into enabling macros by impersonating a DocuSign request. The extracted URLs suggest the macro's purpose is to download and execute a second-stage payload. The presence of 'rundll32.exe' and 'DllRegisterServer' in the DOC BODY further supports 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
1f3a9e9f425000bccc6ecbbba5371f1a3b0a17ea072b52992d451728caf3ab45
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3742 bytes