Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9644794a03fb5c29…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:29:51 Authoring application: Microsoft Excel
MD5: 6699240ce15a00c25dbb6a0fabcfc74c SHA-1: d1cc4e65dd179ea30c1b4d182d9ea91c443ad3af SHA-256: 9644794a03fb5c29d33fd23578472a214f198e828f55ded383b30ec28b32f4ec
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 defined name, which is a known technique for executing malicious code upon opening the workbook. The presence of dangerous formula APIs further indicates malicious intent. The macro sheet itself is heavily obfuscated, preventing a deeper analysis of its exact payload, but the Auto_Open execution is a critical finding.

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
29dd4373012bbcbdcb0469b93483c4ffab7a424ba437ba0dcd56825f89106795		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6508 bytes

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