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

Static analysis result for SHA-256 7035af3e238d22dc…

MALICIOUS

Office (OLE) / .XLS

36.0 KB Created: 2020-11-25 10:31:27 Authoring application: Microsoft Excel
MD5: 4abb815c18f1d481aacab5a2e1c3590c SHA-1: 904408a3009d1b3e94d69d1ec6cd727f1ad23918 SHA-256: 7035af3e238d22dc869c22e7a60b8e5120c0d027e8d79696d60bb630db11c67d
140 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing Excel 4.0 (XLM) macros. The presence of an Auto_Open defined name and the use of dangerous formula APIs like RUN indicate that the macro is designed to execute code automatically upon opening. This is a common technique for downloading and executing further malicious content.

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
d7f9b04b865bc611e0374e2f7e93764cccd76b8fba7a17e9bc77408d4f639900		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6635 bytes

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