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

Static analysis result for SHA-256 308230be8cb6c2ee…

MALICIOUS

Office (OLE) / .XLSX

281.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: ed773bb93fde364a1e63579899e77f69 SHA-1: 61e3c691abb323efe831252acc2fd01826347890 SHA-256: 308230be8cb6c2eefd1379b5c4f46350203fb39c8a61ff6d5f8da88787d48385
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File T1059.001 PowerShell T1105 Ingress Tool Transfer

The sample contains Excel 4.0 macros, specifically an Auto_Open macro, designed to execute automatically when the document is opened. It also contains a lure to enable macros by impersonating DocuSign. The macro uses the URLDownloadToFileA API, indicating it attempts to download a second-stage payload from one of the provided URLs. The presence of the Auto_Open macro and the URLDownloadToFileA API strongly suggests a downloader functionality.

Heuristics 5

  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • 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
593d9cc811b921a2459aef1103deb1492dac145372831476ece792b74b1b8f31
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1668 bytes