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

Static analysis result for SHA-256 4eceea3334822347…

MALICIOUS

Office (OLE) / .XLSX

93.0 KB Created: 2020-05-20 08:20:55 Authoring application: Microsoft Excel
MD5: 61c725c493e319ac696e915c8649493f SHA-1: 1f94b75471dc0f14a73ba7886cf6d8c86685a7c0 SHA-256: 4eceea33348223473c5ad30480b949c2d1fed4464bd19522097b9ddd6c6cf7e2
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 User Execution: Malicious File T1105 Ingress Tool Transfer

The sample is an Excel workbook containing hidden macro sheets and an Auto_Open entry that executes dangerous formula APIs. The document body contains a fragmented URL 'http://os.meduarncbxC/DGVqBLjySRPJYQUMONwlTFiAEg...'. While the extracted scripts are truncated, the heuristic firings for OLE_XLM_DANGEROUS_FN and the ClamAV detection for Xls.Dropper.Agent indicate the intent to download and execute a second-stage payload from the remote server.

Heuristics 4

  • 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.
  • ClamAV: Xls.Dropper.Agent-8001655-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-8001655-0
  • 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
996e869955e72cfbd6adb7c835d255b1c0c3f44c8d9fdb131b846d8e2936a780		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 59657 bytes

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