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

Static analysis result for SHA-256 fb22b2a8989ff53a…

MALICIOUS

Office (OLE) / .XLSX

31.0 KB Created: 2021-01-25 15:58:03 Authoring application: Microsoft Excel
MD5: be72c55ce39212caa5d279539d41a202 SHA-1: 60b623065e5b0c795bf3e4fd98136994994be636 SHA-256: fb22b2a8989ff53a22a5e5b67b7044e9c237e18be5e91514aabb859c96aa1a08
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 macro sheet (XLM) that uses an Auto_Open function to execute. The document body explicitly instructs the user to enable content, a common lure for macro-based malware. The XLM macro sheet contains references to dangerous functions like RUN, indicating an intent to execute arbitrary code. No specific family could be identified, but the technique is consistent with macro-based downloaders.

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
4a042a7b5d482af65f5095b9e78ff2f6ec91180e7c6af21b386707b0acc0691e		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3447 bytes

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