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

Static analysis result for SHA-256 70d74cd984b9a366…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:45:37 Authoring application: Microsoft Excel
MD5: a7995d9444ba2172cf55004b16651bad SHA-1: 23e419d5d9b3cd7a63d8fe096023faec4dec3108 SHA-256: 70d74cd984b9a3661df36fe9c3b81ac3db27020e91785fd35fc93877d363f7b7
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 function, which is a known technique for executing malicious code. The critical heuristic firings indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it is designed to download and execute a second-stage payload. No specific family could be identified from the available evidence.

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
4b2c713b07797f399b2b58537fecfe6ffcfbb90a3279d28e3a65ec6a4dc358b3		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6874 bytes

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