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

Static analysis result for SHA-256 9b7b0e8493bb59d0…

MALICIOUS

Office (OLE) / .XLSX

76.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: 2ce3cc3419cbfc8eb80fcd27197a6dcd SHA-1: 4e7a6471b4a0b1f5e45277f9a33c33f94d8abb4f SHA-256: 9b7b0e8493bb59d0e0b8a7eb8baf1046338d05228c5a6823fdc48f251de26408
120 Risk Score

Malware Insights

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

The sample is an Excel 4.0 macro-enabled spreadsheet that uses an Auto_Open macro to execute. It impersonates DocuSign to trick the user into enabling macros. The macro then attempts to download and execute a payload from a list of suspicious URLs, including 'stumbletrouser.com/hpbifbnnuauj/'. The use of 'rundll32' and 'DllRegisterServer' suggests an attempt to register a DLL, likely part of the 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
95650bf3b083f7d7d2acad78646ed66bc3f66f931aabfdacd33cba28b47a33d6
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2255 bytes