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

Static analysis result for SHA-256 0f4238a14d0c6dbd…

MALICIOUS

Office (OLE) / .XLS

41.0 KB Created: 2020-12-03 22:00:53 Authoring application: Microsoft Excel
MD5: bd5b1a6cac0bb3be1d728867f6ace41a SHA-1: 4a0dc8e67b9438f31ab2d575b1780262881bd8ff SHA-256: 0f4238a14d0c6dbd53c84513df03d0d3be5f8452aa858e2273788690fe7c59dc
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample contains Excel 4.0 macros, specifically an Auto_Open entry, which is a critical finding. The macro constructs a path to 'C:\PROGRAMDATA\a.exe' and uses the RUN function to execute it. The script also contains a URL 'http://cutt.ly/4hnsBiU' which is likely used to download the 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
6628667c75ebc87e5710166425782a80d8797753020b04e5c50fdd7c1461241d		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1249 bytes

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