Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ef8c04684ea4dc35…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:42:48 Authoring application: Microsoft Excel
MD5: 6cb57b3a29a1485b5efe9597e5849882 SHA-1: cb42360ba73bd99e8e3ad06a8c1decf5e0734798 SHA-256: ef8c04684ea4dc351642c38be43db2df2a08615ed7c3de77989864fbc2089bb9
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook containing an Auto_Open function. This function is designed to execute arbitrary code upon opening the workbook, leveraging dangerous formula APIs. The presence of the Auto_Open entry and the use of potentially risky functions indicate a malicious intent to execute code, likely to download and run a secondary 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
6bbe8e4cf9ccb43d03ebe80c465c614f11ad522af5112430e1be1a110453fc2d		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6832 bytes

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