Office (OLE) / .XLSX malware analysis — malicious · dc397a491a236b2f

MALICIOUS

Office (OLE) / .XLSX

77.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-24

MD5: e15ac3f43fbc7f4e3f22a607fc2823ce SHA-1: 5586b903345e26fd41992cecbc509790934869c9 SHA-256: dc397a491a236b2f1de4d67326f757e6f83e7fee15e93fd6c6dd149d1d711070

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN indicate the presence of an Excel 4.0 macro with an Auto_Open function that calls dangerous APIs, specifically the RUN function. This macro is designed to download and execute a payload from one of the provided URLs. The confidence is high due to the clear indicators of macro execution and the presence of multiple suspicious URLs.

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` `2ca0966e93dacad101ceb18f4d58731b5432892fe851526f2fda59486181312c`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	7325 bytes

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