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

Static analysis result for SHA-256 83bd4276c62388ad…

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-25 10:29:37 Authoring application: Microsoft Excel
MD5: 9068929bd5efbef3b81a64176e7700bf SHA-1: ed3a92f393cffb8911a01d233c2f0479836247c2 SHA-256: 83bd4276c62388ad5c7390af75ce68bf438d2a2153686611224696308c50d2bd
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 suggests the macro is designed to execute commands. This points to a macro-based downloader attack pattern, where the initial Excel file serves to execute a payload from a remote source.

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
eef53a00aa059b867cd54305d938cd41e94f6dcf9c7c47ae53477da0b54c245f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6783 bytes

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