Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8a824ecf9cb5044a…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-27 11:37:49 Authoring application: Microsoft Excel
MD5: e620ef8f00800b44ce2eff2b8db6931f SHA-1: f238bb22d1c58eb4476e1305d4f5001fae907f18 SHA-256: 8a824ecf9cb5044af4a65bb85938d500a04638f91e9944e1cf57b8444c6b5eb6
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros, specifically an Auto_Open entry that utilizes dangerous formula APIs. This suggests the file is designed to automatically execute code upon opening, likely to download and run a secondary payload. The specific dangerous formula API used is 'RUN', which is often employed for executing arbitrary commands or launching other executables.

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
94abc1504344faa7007263ec1410eb7270cb874da01a70411307bffe0c293c2c		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6850 bytes

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