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

Static analysis result for SHA-256 a4c9ab25e494f7f6…

MALICIOUS

Office (OLE) / .XLS

70.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-03
MD5: b3f12429a92a00a629b11f1a6e6c7046 SHA-1: d6e96e076704b2b9d2401d6faef3381936185da3 SHA-256: a4c9ab25e494f7f6f2411e1ff709665d708cbf03566716384bd077046ff40d5e
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open function, which is a known technique for executing malicious code upon opening the spreadsheet. The macro sheet contains formulas that reference dangerous APIs, including RUN, suggesting it attempts to execute external commands or download payloads. The extracted URLs are likely the destinations for these payloads.

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
f83c1e7392699acb02f69ec3ffd4b4b11e29d3a6381df4b6ea4e60977f47b16d
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7590 bytes