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

Static analysis result for SHA-256 823cc8162c2b303c…

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-25 10:41:13 Authoring application: Microsoft Excel
MD5: 464ff0bd26d7edc4ed81448032b5ee60 SHA-1: bdda2ed3aaca4932ebf27c727833aa139c9bc92a SHA-256: 823cc8162c2b303c97c22effe76d6b78a469194cfe818ef8ad79d1eb02d9d88f
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros, specifically an Auto_Open function, which is a known method for executing malicious code within older Excel versions. The presence of dangerous formula APIs like RUN further suggests an intent to execute arbitrary commands. The macro sheet itself contains obfuscated data, likely to hide the 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
ba0fa10212e34cd7eae3ce39b2cbf960613e30b85faff181811ddbc006f2f167		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6575 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.