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

Static analysis result for SHA-256 7b215ddee9c2ed14…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:35:44 Authoring application: Microsoft Excel
MD5: 715aedb81121c60496b24470b778d0b9 SHA-1: 97a757b9c60ddee77b39b97957ea6ba5a3fcf8d8 SHA-256: 7b215ddee9c2ed146464c03c413ddc1e042a054017a50cade46b80348a18209a
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN further suggests the macro is designed to execute arbitrary code. This points to a macro-based downloader or dropper, common for delivering second-stage malware.

Heuristics 3

  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
92c01927e21846e4e09e7e8147c47f284f54e85d734958e246a8f9d07b8cbcd4		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6598 bytes

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