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

Static analysis result for SHA-256 983be81aeac92d46…

MALICIOUS

Office (OLE) / .XLSX

70.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-26
MD5: 4c6d829f87a16932709f41bf19dc1575 SHA-1: 275da384998c1b7c7c66c93a58fa2aa62feb047d SHA-256: 983be81aeac92d4668911dffeb9be49eeff5543737e57216da3cf046f089ae2f
140 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros, specifically an Auto_Open function, which is a critical indicator of malicious intent. The macro sheet includes calls to dangerous functions like RUN, suggesting it's designed to execute arbitrary code. The presence of multiple URLs within the macro sheet indicates a likely download and execution chain for a second-stage 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
699e21f010c7c5f5713063f52e691ec519f766e81393f8793f7a585cd43d5349		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7635 bytes

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