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

Static analysis result for SHA-256 05d9402d95ae6510…

MALICIOUS

Office (OLE) / .XLSX

35.5 KB Created: 2020-11-25 10:41:10 Authoring application: Microsoft Excel
MD5: 809214edf1bc43575ebfc24401162bc3 SHA-1: e375e3ccdd6604500f1a6551271955a1af04c1e7 SHA-256: 05d9402d95ae65104477b02bd6353d6cdfb72406025af0fae4af9a5b7f483ee8
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 method for executing malicious code. The critical heuristic firings indicate the presence of dangerous formula APIs within the macro sheet, suggesting it's designed to run arbitrary commands. The macro sheet itself is likely responsible for the initial execution of a 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
66567b95c8629338a5a67d347ed32b356f9db2add178403bc59370ac38de41ab		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6505 bytes

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