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

Static analysis result for SHA-256 ccb553ffa1cf6ae8…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:47:08 Authoring application: Microsoft Excel
MD5: 681a8ff2718c745f9d64dfa5472e07c6 SHA-1: ba45367e686fbe4789be8209ce8b8afb3c9bcd39 SHA-256: ccb553ffa1cf6ae82ff02243cd8eb0cffab60994bb5ae659c136328d4aa29ce7
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates the workbook is configured to automatically execute macros upon opening. The presence of dangerous formula APIs like RUN further suggests malicious intent, likely to execute arbitrary commands or download further payloads. No specific URLs or hashes were extracted, but the technique itself is highly indicative of malicious activity.

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
6033fdcd12a0d80fcd6bd5d3da3f008b39af0b4b71c91c6b00f5cd4baf80e1dc
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6515 bytes