Office (OLE) / .XLSX malware analysis — malicious · 02e7936cc872b9d2

MALICIOUS

Office (OLE) / .XLSX

236.0 KB Created: 2020-05-21 08:13:54 Authoring application: Microsoft Excel

MD5: e746cb6e32fb5dd960fd1fdd1d7a243b SHA-1: 80562666386f4b75ff520b72700be0d4028ea6cc SHA-256: 02e7936cc872b9d2fd6ee299826c4fa9799546ea61178ef738cec8afe0e1d763

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The critical heuristics indicate the presence of an obfuscated Excel 4.0 Auto_Open macro. This type of macro is commonly used to download and execute further malicious content. The obfuscation suggests an attempt to evade detection. The specific macro sheet file 'xlm_macros.txt' is identified as a key artifact.

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.
Obfuscated XLM Auto_Open execution chain critical OLE_XLM_OBFUSCATED_AUTOEXEC_CHAIN

Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and an obfuscated formula execution chain. The macro builds strings through FORMULA(CHAR(...)), primes state with SET.VALUE / GET.CELL / GOTO, and transfers control through RUN(). This is a high-confidence XLM malware pattern.
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` `77d849b10019517a2944b319ff3d7ee66d653db344e88f0baa37dde38613cfb9`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	130699 bytes

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