Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 cf8aaa7729bc1438…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:47:32 Authoring application: Microsoft Excel
MD5: 0eebd18581cacd0cc8869ae381e787e6 SHA-1: 3b9a9cd2e0e1896ee34b224840d5c2f834297a2c SHA-256: cf8aaa7729bc143859b4ff8780e89039bec1f4b3c3e33ccb13133207fc22484f
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 critical indicator of malicious intent. This technique is often used to automatically execute code upon opening the document, likely to download and run a secondary payload. The presence of dangerous formula APIs further supports this assessment.

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
0f7fc7e427ec50629741351b82df097d73ddeae65da38a3a5e4bf1ad8cc1c774		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6918 bytes

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