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

Static analysis result for SHA-256 d553238215e2eee3…

MALICIOUS

Office (OLE) / .XLS

36.0 KB Created: 2020-11-25 10:43:19 Authoring application: Microsoft Excel First seen: 2022-04-23
MD5: 12287f5f4e8f9655ed01a5ccafe689c8 SHA-1: f8eb6c1f9f99ee877f652aec5ecec652a8e839fb SHA-256: d553238215e2eee33893735019dfe83d658ba5885150aeb5ec5d3739012c645d
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file is an Excel 4.0 macro-enabled spreadsheet. Static analysis detected the presence of an Auto_Open defined name, which is a common technique for automatically executing malicious code upon opening the document. The heuristics indicate the use of dangerous formula APIs, specifically the RUN function, suggesting the macro attempts to execute arbitrary commands. The specific command executed is not fully recoverable from the provided evidence, but the presence of the RUN function is a critical indicator of malicious intent.

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
f06eaadc9f035f813abd5106b234ec90e98c31bc5886dfa4a14f2605e41e6ffa
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6454 bytes