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

Static analysis result for SHA-256 4b73bc014d8e2d7a…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:42:54 Authoring application: Microsoft Excel
MD5: 297cfbd28e465f75a33ba28cbd2c64e4 SHA-1: ea460a03f0831dbfa58686abfd1ccf97739bfa9f SHA-256: 4b73bc014d8e2d7a10b11b2934c06ac33c7bfcbd777d982593713d7b056e798c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. The presence of dangerous formula APIs like RUN further confirms this. While no specific URLs or hashes were extracted, the Auto_Open macro is designed to execute arbitrary code, strongly suggesting it acts as a downloader for a second-stage payload.

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
b631ea598e824bf2dfa64dcd4abba1c4eb6ac5669e3f9ff18705e5919ca31e22		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6337 bytes

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