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

Static analysis result for SHA-256 cbf30d26d5bc07be…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:40:40 Authoring application: Microsoft Excel
MD5: 5d9287855c877f16db85eeb69c7a6695 SHA-1: 16756f88c0e78a3ff18a948b6f69f66837436bcd SHA-256: cbf30d26d5bc07be226310659607b5324262081c807f9b3243fada87c10f3543
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a known technique for executing malicious code upon opening the workbook. The critical heuristic firings indicate the presence of dangerous formula APIs like RUN=0, suggesting the macro is designed to execute external commands or download payloads. No specific URLs or hashes were extracted, but the presence of Auto_Open strongly implies a malicious intent to run arbitrary code.

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
93930d1d2d1e1cde9d6391cd20ebef218dac26aa18067d2bbfa9e57dd563b709
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6539 bytes