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

Static analysis result for SHA-256 73ffa57145be2aa8…

MALICIOUS

Office (OLE) / .XLS

209.5 KB Created: 2021-02-06 22:23:31 Authoring application: Microsoft Excel
MD5: 20e59a772c6e5623c4943e1d56d1f8ef SHA-1: 292d15f9fdd114b4ec45f10b28dcf11f49e6b612 SHA-256: 73ffa57145be2aa80790a767193c2a81091e3540e3269474740a315d074496a3
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a common technique for initial execution. The macro script explicitly constructs a PowerShell command to download a file from 'https://tinyurl.com/1na4z0gm' and execute it. This strongly suggests a downloader or droppper functionality.

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
20e224fc52404f96d6691a63ca855040917a373bf47ae760cd32faa38f7567bd		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1242 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.