Office (OLE) / .XLS malware analysis — malicious · 3a8961729da3d80e

MALICIOUS

Office (OLE) / .XLS

41.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel

MD5: b5ec19816be3286c1ad211803d1c39eb SHA-1: 40cfe862b504177d0711bddcb31c42378be6a0c3 SHA-256: 3a8961729da3d80ede6288545a89494f3b9b2091e37d77456a677a94f4080142

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file is an Excel 4.0 macro-enabled spreadsheet. Static analysis detected an Auto_Open function within the XLM macros, which is a common technique for executing malicious code upon opening the document. The presence of dangerous formula APIs like RUN indicates the macro is designed to execute arbitrary commands. The sheet name 'OsxJT' is also extracted as a potential IOC.

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.

Filename	Kind	Source	Size
`xlm_macros.txt` `8056b152ae14c53209648b550bea62ac0a490cb369cdc2ac83ebdae583b7a57a`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	7983 bytes

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