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

Static analysis result for SHA-256 3bd9016fe2b5f4c8…

MALICIOUS

Office (OLE) / .XLSX

31.0 KB Created: 2021-01-28 13:26:10 Authoring application: Microsoft Excel
MD5: 5303afa0d471a0d4a51d33e8913f4c66 SHA-1: cde7646b5c6f509505df505f1020199a1ad4546d SHA-256: 3bd9016fe2b5f4c8ca553d003f64be95c7d40aede819faed7e9e343c4849d2ae
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 User Execution: Malicious File T1059.005 PowerShell

The sample is an Excel 4.0 (XLM) macro-enabled workbook. It contains an Auto_Open macro that uses dangerous functions, specifically the RUN function, indicating an attempt to execute arbitrary code. The document body explicitly instructs the user to enable editing and content, a typical social engineering lure to bypass security measures. No specific malware family could be identified, but the techniques used are consistent with macro-based malware delivery.

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.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
e2215f3ceda042950ca9c0f5f8a27f5f03fffa26972eda63dad46444f004f311
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3424 bytes