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

Static analysis result for SHA-256 9f0a13ce9d7d5a18…

MALICIOUS

Office (OLE) / .XLS

85.0 KB Created: 2020-07-02 15:46:44 Authoring application: Microsoft Excel
MD5: 90c76c03e2bb25c6ffd49420a0dcc6ad SHA-1: 1b59ee1ac334a265f23699713bdec6b4ac2afc23 SHA-256: 9f0a13ce9d7d5a185eed46bdbac9dde95e14d2e9f7ca74378d461120c781a3f6
160 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File

The sample is an Excel file containing Excel 4.0 (XLM) macros, specifically an Auto_Open macro. This macro is designed to execute automatically when the workbook is opened, and it utilizes dangerous formula APIs, including the RUN function, indicating an intent to execute arbitrary code. The presence of a macro-enable lure further suggests that the user is expected to enable macros for the malicious payload to execute. No specific IOCs like URLs or hashes were extracted from the macro itself, but the technique strongly suggests a downloader or initial execution stage.

Heuristics 4

  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
9ca1ca8d2cae4729cbdd180d70db49022450b795a148a7dfbf738f144392b12f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 31011 bytes

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