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

Static analysis result for SHA-256 69daab1bffe08609…

MALICIOUS

Office (OLE) / .XLS

37.0 KB Created: 2020-11-25 10:57:48 Authoring application: Microsoft Excel
MD5: f01ee703b0242970744c01c231187e5f SHA-1: 4c38e3c58f76e390f5a6b3798dbf832cc31b6a50 SHA-256: 69daab1bffe08609e278d3db2dd9bd4d1351971a5f1ae273c71301546b9d9863
140 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing Excel 4.0 macros. The critical heuristics indicate the presence of an Auto_Open function, which is designed to execute automatically when the workbook is opened. This function likely contains commands to download and execute a malicious payload, a common technique for initial execution and further compromise.

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
062d28b064df89d7aa314f5be37a282760e1785af6f92d91f10a86476976bc42
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6609 bytes